ExponentialDecay

The short answer is that you never stop looking at the literature until the project is done. Even as I was sending in my final edits in response to the referee report last week, I was still searching the literature for articles relevant to my work. Maybe I won't find anything relevant to add to my article, but I must stay up to date on the literature (so I keep reading even if the project is done because it will help for the next one!)
But, if you are asking a more specific question, like "How much preparation do I need before I start grad school" then that's just up to you. You shouldn't need to do anything until you begin this fall, but if it makes you feel better to read, then do so  One tricky thing is that unless you are continuing something you already have experience in, you might not know the seminal works that your advisor could suggest, so I'd start by asking them! It's okay to email your advisor over the summer and ask if there are any suggested summer reading. 

I am really sorry to hear that your situation is not getting better despite you continuous efforts. After reading your post, I just wanted to point out few things that I've noticed. Since I do not your full story, please ignore the points that might not be relevant:
1) You have a huge pride on your previous degrees (top 20 unis, top 5 programs and etc...). While these are great achievements, people would like to see WHAT you did rather than WHERE you received your training. Don't get too fixated on your awesome academic history, focus on building your awesome practical/research/professional experiences that you can talk about in the interviews. Maybe one of the reasons why you were not successful in getting into PhD programs is because you are aiming for "top schools" or "top institutions." 
2) School, program, and GPA do NOT define a person outside of academic world (mostly). You have teaching and social work credentials so working with inner city schools as a teacher or a social worker would allow you to get the field experience you need to get to the director or middle management role that you want. Just having Master's and PhD alone will not qualify you for middle management jobs. 
3) PhD requires evidence of research efforts. Looks like your Master's degrees were professional degrees without research components. I would urge you to work as a research assistant or research coordinator under social work or educational psychology profs for 2 years before you apply for PhD programs again. Building your relationship with profs in the field is a good way to get awesome reference letters. 
4) There is no ONE job or opportunity that will set you for a successful career path. You need to get your hands dirty and look for lower level positions. Most importantly, you need to commit to a field of work (educational policy? history? mental health? child welfare? homelessness ????? what is your interest????). 
As others said, I think more schooling is not a solution for you at this point. I really do hope this help! 

For a PhD applicant, a 3.5 GPA is not a very good GPA. It's just enough to not raise eyebrows - assuming this is cGPA, not GPA in major. Average admitted GPAs in PhD programs range from A- to higher.
5 or 6 acquaintances of mine graduated with their education masters in this most recent class. All of them from top programs. Those of them who are not working at entry or mid-level positions in run-of-the-mill schools and districts are all on temp contracts or doing internships. The ones who are doing work that I, an outsider, perceive as more prestigious have previous relevant work or academic experience (e.g. one got a nice opportunity in POC empowerment, and she has been doing race work since her undergrad thesis). I get the feeling that the field is competitive and a degree doesn't guarantee you a job.
I think you're right. You don't say what your field is, but it seems like you've gotten a lot of unrelated degrees, not just subject-wise, but in terms of how they connect to your career. It seems like you got a degree in one professional field, but didn't work in that, then in another, didn't work in that either, and so on. Rightly or wrongly, you seem flaky. I struggled to get my first job out of undergrad as well, it is NOT easy out there, but I think, at a point, it may be worthwhile to stop getting degrees and consider if it's something else, like your soft skills, that needs attention.
Another factor is that, and I'm trying to put this nicely (I really am, mods!), your expectations are unrealistic. It is not possible - it is almost certain that you will not become a professor. That you would be "content" with a director role anywhere is likewise out of touch. These are all extremely competitive positions that aren't just handed out to people with 3.5 undergrad GPAs. They aren't handed out to people with 3 publications in top journals and a PhD from MIT either. You need to be an expert in your field, an exceptionally hard worker, and well-liked by your colleagues to get them. There is also a not-insignificant element of luck. Most people with PhDs don't end up in those jobs.
lol  To quote something I read on the internet, the DC metro sets itself on fire every day.

For a PhD applicant, a 3.5 GPA is not a very good GPA. It's just enough to not raise eyebrows - assuming this is cGPA, not GPA in major. Average admitted GPAs in PhD programs range from A- to higher.
5 or 6 acquaintances of mine graduated with their education masters in this most recent class. All of them from top programs. Those of them who are not working at entry or mid-level positions in run-of-the-mill schools and districts are all on temp contracts or doing internships. The ones who are doing work that I, an outsider, perceive as more prestigious have previous relevant work or academic experience (e.g. one got a nice opportunity in POC empowerment, and she has been doing race work since her undergrad thesis). I get the feeling that the field is competitive and a degree doesn't guarantee you a job.
I think you're right. You don't say what your field is, but it seems like you've gotten a lot of unrelated degrees, not just subject-wise, but in terms of how they connect to your career. It seems like you got a degree in one professional field, but didn't work in that, then in another, didn't work in that either, and so on. Rightly or wrongly, you seem flaky. I struggled to get my first job out of undergrad as well, it is NOT easy out there, but I think, at a point, it may be worthwhile to stop getting degrees and consider if it's something else, like your soft skills, that needs attention.
Another factor is that, and I'm trying to put this nicely (I really am, mods!), your expectations are unrealistic. It is not possible - it is almost certain that you will not become a professor. That you would be "content" with a director role anywhere is likewise out of touch. These are all extremely competitive positions that aren't just handed out to people with 3.5 undergrad GPAs. They aren't handed out to people with 3 publications in top journals and a PhD from MIT either. You need to be an expert in your field, an exceptionally hard worker, and well-liked by your colleagues to get them. There is also a not-insignificant element of luck. Most people with PhDs don't end up in those jobs.
lol  To quote something I read on the internet, the DC metro sets itself on fire every day.

I don't doubt that you're capable of doing PhD-level work, but from your writing it doesn't sound like a PhD is a good career move for you right now. I think you are much too focused on the joy that a doctoral program will bring you, and I doubt that any program could measure up. Grad school doesn't generate instant happiness, and neither does a job as a university professor. I think it's important to be realistic and realize that getting such a job is incredibly difficult. For someone who's been drifting and has done three masters degrees, I think it's a concern. I didn't read anything in your post that convinced me that you should actually do a PhD. You don't sound focused on a particular field or question; instead, you're attracted to a mystical perfect job post-PhD that doesn't exist. It's important to realize that a PhD is a long and difficult road, and that the majority of people who go into it will not get a job as a professor. Don't go into it only to get that outcome, because it's just not realistic. I think instead it might be a good idea to do two things. One is get help improving your mental health. The other is try to think about career goals, broadening your sights beyond academia.

@MKPolicy
I'll just be straightforward: I don't think you should do an MPA.
First,  I don't sit on any committees (and neither does anyone else commenting here), but that qGRE will preclude admissions to HKS and WWS, and potentially a few others, because it's a spectacularly low qGRE for those programs and also because your profile isn't exactly what they're looking to admit. On paper, you don't look like the academic type - low GPA from mediocre undergrad, and yeah you have a 3.75 in your master's, but it is generally expected that you will have close to a 4.0 in a master's program, plus, as anyone in finance will tell you, finance programs vary drastically in quality. The qGRE is kinda the nail in that coffin. Policy schools aren't as anal about prestige and other gold dust as law and business schools, but they still care a great deal about how glitzy you are, on an ordinal scale. 
Second, I'm not sure that an MPA is going to help you. You're already older than 99% of the people who already have their MPA and are applying for typical post-MPA jobs. You're actually older than a lot of the people who are a step above that. I don't pretend to know everything about all the employers that hire MPAs, but I'm trying to say that it's moreso an early-career degree than a mid- or late-career one, and the portions of the policy field that I am familiar with are very attentive to that. My organization gets a lot of CVs from people whom we perceive to be overqualified precisely in the way you would be overqualified for graduate entry-level positions, and I've only seen people prefer to hire the typical candidate over someone with too much experience.
Third, I don't think you need this degree. An MPA isn't going to help you get elected into any kind of office. It's not going to teach you in-depth estimation techniques (HKS ID people, yes, this is the hill I die on). An MPA isn't going to make you any more qualified to work for the IMF or WBG - if you want to work with economics or finance, you are already qualified enough to do that (plus, people prefer to hire degrees that speak to someone's concrete skills, not generalists with MPAs who can code Stata but don't know how to estimate a regression with an interaction term - I am not kidding, people, this is why you don't get an MPA to learn statistics), and if you want to work with something that isn't economics or finance, you don't have enough field experience, period, and a 2 year master's isn't going to make up for it like at all. An MPA is what you get when you want to be a mid-level bureaucrat in a salaried position (seriously, the height of anyone's ambitions here). If you want to transition into this field, you need to network and transition in your career. It takes knowing someone more often than not, but it's feasible to transition from what you're doing now in the private sector to doing something similar in the public sector. I doubt that will scratch your itch of helping others, though (it scratches mine, but my itch is extremely particular and gets me thrown out of more liberal bars). If you want to get elected into office, I can't even begin to imagine what that takes, but an MPA isn't it.
If you still want to get a degree, I'd recommend the 1-year executive MPA at Harvard.

I second this (or third it, or hundred it, or thousand it etc.). As I mentioned in the thread that ExD cited, the GRE scores are important (mainly the verbal on the GRE general), but you probably don't need to achieve much better than the 90th percentile to be competitive. I personally struggle with standardized tests like the GRE because I have a hard time filtering out possible answers from the purportedly "best" answers...but having a 90th percentile verbal didn't seem to hurt me in either round of applications. 

Speaking to the broader point of your thread, however, there really doesn't seem to be one "biggest factor" in acceptance. Conventional wisdom around here (based on experience, first- and second-hand observations, and just plain common sense) suggests that the WS and the SOP are the one-two punch of important factors...though some programs may have invisible GPA and GRE score cutoffs. That being said, even though most successful applicants in the past have undergraduate GPAs higher than 3.7, GRE verbals higher than 90th percentile etc., there are too many exceptions to make it a rule. Ultimately, you want to have every single element of your application as strong as it can be, but you absolutely have to have a strong WS and SOP. I've said it several times elsewhere on this forum (including in the above-cited thread), but both my SOP and WS went through several rounds of revision, based on the feedback of several professors and other grad students. It was a "good" paper to start with, but I whittled, honed, cut, added, showed people, whittled, honed, cut, added some more (etc. etc.) until everyone said "yes, that's very good"...either out of sincerity or exasperation! But it worked for me, and that revise-rinse-repeat process seems to have worked for most successful applicants who have come through here, so perhaps there's something to be said for conventional GC wisdom.

 

Unless you are an exceptionally bad test-taker or ESL, I'm not sure of the utility of treating GRE prep like a full-time job. All you need on the GRE is to get a respectable score. The WS deserves all the extra time you have to spare.

You may not get many bites on your question because there's a really long thread devoted to this issue -- it may answer your questions if you read it first.
This one: http://forum.thegradcafe.com/topic/23492-the-am-i-competitive-thread-read-me-before-posting/?page=37
 

Adding to Bill's excellent response:
You need to specialize in the field you are most passionate about.  It's not about improving your odds at a job five years from now.  It's about doing your best work in a field where you would then be spending 30+ years of a career.  I really like Chaucer.  I'm incredibly fond of Victorian novels.  I dig comics and graphic novels.  But I can't imagine spending 30 years working on any of those topics.  But Renaissance drama?  I LIVE for that.  When I teach it, I come alive and I never tire of seeing it, thinking about it, and writing about it.  Whichever field gives you that feeling, THAT'S the field you should specialize in, because the work you do in that field will stand out on the job market, whether you are up against 20 competitors or 200.

By way of support, you are not alone in the sentiment of "I don't understand how I didn't see the signs earlier." A lot of parents and partners are surprised when they discover their children/spouses go from, say, turning religiously observant to turning up in Syria. That's a simplistic characterization and the radicalization is different to your husband's experience, but that is roughly a pattern that's observed everywhere and across the radicalization spectrum, from high school mass shooters to Taliban recruits.
So you're not alone in missing the signs. Sometimes it happens glacially, so slow that it's almost imperceptible, especially with a loved one.
Nobody has found a perfect way to deal with a situation like that. But I would suggest you seek support. See if you might talk to someone you are comfortable discussing this issue with -- a parent, a sibling, friend or coworker...someone dependable that can maintain confidentiality and has close rapport with him if it is necessary that they talk to him, though there's so much that a 'talk' can accomplish when it comes to radicalization/extremism. The idea is mostly for you to have support from a trustworthy source. Only someone like that, who knows the nuances of the situation better than us here, can help you talk through ideas and options.
I wish you courage.

Good. Because you have offered some comically dangerous advice. 
 
He only has to get "physically aggressive" once for your advice to turn out poorly for OP.  The guy only threatened to divorce his wife because she won't let him hang a Nazi banner. He sounds really stable and like the kind of fellow who is unlikely to get physically aggressive.
 
Are you for real? 
 
Holy mother of God, no! This advice is bad enough when offered to people in non-threatening relationships ....
 
OP:  fuzzy hit the advice head on. Please take care of your physical and emotional health. If want to try to help your husband, that is great (I think). But please don't believe that it is your responsibility or that you alone can change him. 

I think it's important to be realistic in this situation. While my ex was never a white supremacist, he was against feminism, belittled my field, spoke negatively of the social justice movements, etc. So I understand where the "how did this happen" or "did I miss the signs" thoughts come from! But please don't do that to yourself; none of this is your fault. 
It is admirable that you want to educate him or change his mind, but I have to say I'm not sure that will work. Many people enter into relationships with people they know are flawed thinking "I can change x." But they can't change whatever that behavior is; and I don't think you will be able to change your husband's mind. People are stubborn creatures, and until your husband realizes he's in the wrong and decides he wants to change, it won't happen. Losing you might be the catalyst he needs to start that change. But you're living with someone who puts your field down (and by extension, you as well) and disagrees with you on fundamental issues. Don't put yourself through that!! I understand feeling conflicted; it took me a while before I convinced myself to leave my ex. This is your life, not his. If you're not happy in the relationship, or you know you can't be satisfied with this man, then leave. Do what you need to do to be happy in life. If your husband is no longer part of what makes you happy, so be it. 
I hope you stay strong, peaceful, calm, gracious, and loving. Don't let the hate win. Hang in there!!! <3

Okay, I'll voice the possibly less popular opinion. Your responsibility is to yourself. You don't have to stay with him and you are not responsible for getting him better or for educating him. You need to take care of yourself. If you do decide you want to try and stay, I think it's of utmost importance to get support from others. Can you involve his family? friends? do you have a support system around you to take care of you, if you need it? If he wasn't always like this, something must have triggered this, and maybe you can help him through it. Whatever it is, though, you shouldn't do it alone, and you shouldn't let him take it out on you. This sounds like a situation that requires professional help. I know that posting here was probably already hard enough, so maybe the next step is for you to find counseling on your own, maybe through your school, before you think about talking to him. Figure out your resources and support network, then come up with a plan to confront him. I hope that there is no fear of physical violence, but if there is, let me repeat again: your responsibility is to yourself first. Make sure that you are safe, and take care of yourself, both physically and mentally. If that means you need to leave him, I think that's totally understandable and no one from the outside can judge. And if you choose to stay and try and fix it, again I hope that no one will judge and that you can find the help you need. 

@MKPolicy
I'll just be straightforward: I don't think you should do an MPA.
First,  I don't sit on any committees (and neither does anyone else commenting here), but that qGRE will preclude admissions to HKS and WWS, and potentially a few others, because it's a spectacularly low qGRE for those programs and also because your profile isn't exactly what they're looking to admit. On paper, you don't look like the academic type - low GPA from mediocre undergrad, and yeah you have a 3.75 in your master's, but it is generally expected that you will have close to a 4.0 in a master's program, plus, as anyone in finance will tell you, finance programs vary drastically in quality. The qGRE is kinda the nail in that coffin. Policy schools aren't as anal about prestige and other gold dust as law and business schools, but they still care a great deal about how glitzy you are, on an ordinal scale. 
Second, I'm not sure that an MPA is going to help you. You're already older than 99% of the people who already have their MPA and are applying for typical post-MPA jobs. You're actually older than a lot of the people who are a step above that. I don't pretend to know everything about all the employers that hire MPAs, but I'm trying to say that it's moreso an early-career degree than a mid- or late-career one, and the portions of the policy field that I am familiar with are very attentive to that. My organization gets a lot of CVs from people whom we perceive to be overqualified precisely in the way you would be overqualified for graduate entry-level positions, and I've only seen people prefer to hire the typical candidate over someone with too much experience.
Third, I don't think you need this degree. An MPA isn't going to help you get elected into any kind of office. It's not going to teach you in-depth estimation techniques (HKS ID people, yes, this is the hill I die on). An MPA isn't going to make you any more qualified to work for the IMF or WBG - if you want to work with economics or finance, you are already qualified enough to do that (plus, people prefer to hire degrees that speak to someone's concrete skills, not generalists with MPAs who can code Stata but don't know how to estimate a regression with an interaction term - I am not kidding, people, this is why you don't get an MPA to learn statistics), and if you want to work with something that isn't economics or finance, you don't have enough field experience, period, and a 2 year master's isn't going to make up for it like at all. An MPA is what you get when you want to be a mid-level bureaucrat in a salaried position (seriously, the height of anyone's ambitions here). If you want to transition into this field, you need to network and transition in your career. It takes knowing someone more often than not, but it's feasible to transition from what you're doing now in the private sector to doing something similar in the public sector. I doubt that will scratch your itch of helping others, though (it scratches mine, but my itch is extremely particular and gets me thrown out of more liberal bars). If you want to get elected into office, I can't even begin to imagine what that takes, but an MPA isn't it.
If you still want to get a degree, I'd recommend the 1-year executive MPA at Harvard.

@MKPolicy, you have an extremely interesting profile. To be honest, most people here are probably much younger than you, and have much less varied career experiences. In general, you should be a pretty strong candidate given how you're representing yourself, and of course, if you do more work to get your quant score up. Don't worry about your undergrad GPA. Your undergrad was approximately fifteen years ago. I'm pretty sure that at this point, admissions committees just want to make sure you graduated from an accredited institution, and that you haven't been spending your life since then under a rock. 
What I'm curious about (and what admissions committees will want to know) is why you're going for another degree. The WWS MPA and (I think) HKS MC/MPA are quant heavy, but you already have a graduate degree in finance and economics that you just graduated from not long ago. Why are you going after this one? Where will it bring you that the former degree and your very quant-y sort of job experience won't? It'd be compelling to hear that you're contemplating a career change or looking to transition into another role at your organization or taking another similar step. Otherwise, it could sound like you're just preoccupied with the prestige that comes with the kind of school you're applying to.
I think this sounds like your weakest point so far, so definitely put some effort into writing a stellar SOP and getting multiple reads on it. Your GRE score doesn't even seem as important in comparison, because you have a job that demands a good understanding of quantitative concepts, so they'll understand that 151 obviously doesn't reflect everything. Besides, after a certain point, higher GRE scores don't increase your likelihood of acceptance - they just increase your likelihood of getting financial aid. If you're most concerned with being accepted in the first place, focus on your SOP. Good luck!
 

But if the rankings are commonly accepted as garbage, why should they reflect on the quality of your credentials one way or another? Similarly, what about the first-gen, low-income, nontraditional students of color who were accepted into highly respected schools that did not place well on these rankings? Should they feel as upset as you are satisfied? If so, doesn't it seem like a zero-sum game wherein everybody has a lot of emotions and nobody wins?

London, Manchester, and Liverpool are cities in England. England is not a city. 
May I suggest that you just take some time off to travel in Europe? Studying an entire degree in a country you know absolutely nothing about isn't exactly the best idea anyone's ever had. Moreover, living and traveling in a place are two very different things. It sounds like you might benefit more from doing some traveling and soul-searching (or, in other words, growing up), and not necessarily from committing to a multi-year intense advanced academic program, where I would be willing to bet that you don't know what your end goal is or what career you'd want to pursue. I say this because degrees from the UK or Germany will give you different career opportunities than a Canadian degree, and to know which one is right for you you need to know something about your research interests and long-term career goals. Traveling and exploring could be a good way to figure that out.

On the contrary, perhaps I should've phrased my answer clearer: jobs in the IR industry do not pay enough money to pay down that debt. You shouldn't be taking out that loan for a degree in money tree horticulture, if your goal is to work in IR afterwards. Caveat, this is my personal opinion, as someone who likes to have savings and doesn't want to live with roommates when I'm 40. This is America, not Cameroon, so of course you won't be living in a cardboard box in an alley, but you will most likely face significant financial sacrifices.
NGO jobs pay 40-50. Fed jobs pay 50-60. Private sector jobs pay a bit or a lot more, depending on what private sector specifically, but if that's your goal, you're better off getting an MBA. I live in the District, where I pay a third of my salary in rent (and I make more than the numbers I quoted) and I live with roommates. Studios start at 1300 in Petworth and 1700 anywhere you want to live (without utilities). I found my place via Craigslist, where most of the other people in my price range were in their mid-30s. I have a friend in his early 30s who just got really excited at hitting the high 60s in salary, and he's in a quanty field. The metro costs ~$3 a ride depending on from and to, a taxi is $10-15 for short distances, a coffee is $3-5, lunch is $10 self-service or $25 sit-down, drinks are $6+ at happy hour, a quart of milk is ~$2, basic white eggs are $2, a big bag of Doritos is $5. Sales tax is 5.75%. You're paying 20-30% of your salary in various taxes before you take it home. Add a, what, $800 monthly loan payment to all that, and you're squeezed pretty tight.

Pay better attention to wording: not worth it for that amount of debt. They're good programs, but this industry won't allow you many opportunities to pay down that kind of debt. This is why people need to have industry-specific work experience before signing up for such a degree. You try living in DC on a 50k salary, and suddenly the financials become a lot clearer.

Any particular reason you feel the need to analyze this?
 

One way to possibly minimize your risk is to go with an MPP, which is a more flexible degree.  I did a dual MPA/MAIR at the Maxwell School, and a surprising number of those of us who did the dual degree ended up working in local government, which can end up paying better than a lot of NGO jobs. It's easier to market yourself to a local government or otherwise domestic policy-focused job from an MPP than it is from an IR degree.  That can come in handy if, for example, you realize you really don't want to live in DC, New York or abroad.
I'd think carefully about specifically what kind of work you want to do. My fellow Maxwell alumni and I have so many different kinds of jobs that require very different types of skills.  For example, I do policy research, for which the statistics and economics skills are quite useful, while others are more involved in program coordination and contract management types of work.  Some folks work in very finance focused jobs (e.g. bond rating agencies).  Maybe neither of these degrees is the right one for you.  Not going to grad school now and getting some work experience instead as others have suggested might be a better option. A handful of folks I studied with at Maxwell, mostly those that didn't have a lot of prior work experience, ended up later getting another master's degree in a different field (e.g. finance, or in one case nutrition) when they had a better sense of where they wanted their career to go.

Most English programs allow you to take classes in other departments. All worthwhile PhD programs in the US are fully funded. If one isn't, it's predatory and it doesn't actually want you to attend.
This is a cute OP and I feel like it has purpose. That said, it's kind of hard to advise you because you don't say what your research interests are. That will guide your program choice much more than your desire to take classes in the philosophy department. Not to mention, philosophy departments, just like English, differ in focus and strength and the classes they offer. If your interests are sufficiently interdisciplinary, an English program might not even be the right fit for you and you might need to apply to interdisciplinary programs. That's only if you know for certain what your project is, because grad school really isn't the time for self-exploration for the sake of self-exploration.
As for lack for undergrad prestige, I'm not sure it's so much that that holds people in your situation back (though it is a factor, among hundreds of factors). The thing in common that applicants from low-ranked UGs and applicants from prestigious non-US universities seem to have in common is a lack of polish. Like, an OP from an applicant from a top US undergrad contains much different questions, assumptions, and information because they are more likely to know what's up. They have more information and support from their department in preparing for grad school. Presentation and register of your materials ends up mattering a great deal, and that's something most people struggle with if they didn't spend time in an environment that runs by those rules. Good news is, unlike prestige, that's all fixable.

I'm not attacking you personally. I'm pointing out that you tend to make brash statements about inconsequential things and not back up what you say with any evidence, which is about as personal as saying that your methodology sucks and that's why your numbers don't make sense. 
I mean, you're the one who came in here and were like, Princeton is MUCH better than Harvard, with no justification whatsoever. You seem to be implying that people should trust you because you're you. So, for a change, how about you make a point? Not that I'd like you to further beat this spherical horse in a vacuum, because to me this seems like a completely pointless, baseless argument that you must be making because you're bored or something. They're both good schools that place people with good employers. I don't understand why you need to get in here with an investigation of differences that don't matter even if they do exist.

@went_away you really love inventing pointless arguments out of nothing and getting really worked up about it, I see.