I did the long distance thing for ¾ of my MA program and will likely be facing it again at some point during the PhD (my husband is not an academic, but his job likes to move him around). It is a very hard decision to make and definitely not right for everyone. While I hated being away from my husband, it did work fairly well. Friends who actually lived with their partners during school frequently told me how lucky I was.
It sounds terribly selfish, but there is something to be said for being in a supportive relationship during grad school without having to deal with day to day issues and couples obligations. If I wanted to work late or work all the time, I did. If I wanted to eat dinner at odd hours, I did. Sometimes it was pretty handy to only worry about myself and not mess with coordinating schedules. We only saw each other over the Christmas, Spring, and Summer breaks, so when we were together, we were able to focus on important things and spend more quality time together.
On the downside, my friends that lived with their partners had someone to go home to at the end of a bad day (phone calls can’t even come close to that), someone to bring soup when they were sick, someone to celebrate successes with, and someone to bring to the department Christmas party. If I didn’t have such an amazing friendship with my roommate and a few of my fellow students, I’m not sure I would have been able to handle the distance. It was hard not getting to experience the minutiae of everyday life with my husband and it was hard not to be there for him when he had a bad day or to be able to take care of him when he was sick.
It did help to always know the next time we’d see each other and to have an end point in mind. Text messages and Skype are pretty helpful as well. Happy thoughts for everyone that has to make the long distance decision!