GUYS, THANK YOU SO MUCH for all those suggestions/advice/experience-sharing!!
I am actually seriously thinking about this now-before starting this thread I am just trying to postpone the decision as much as I can and avoid the talk between me and my bf (sounds very childish I know).
Our situation is a little bit different...because 1) we are both international student; 2) we are gay and still in closet. Those two things together make me feel that it will be easier for both of us if we can just simply stay together. But just as some of you have said, I am starting to realize that this is probably not the way things work. As international students we need to fight together, but each towards my or his own career goal, so that we can ultimately stay in this country, where we can have equal rights and actually get married. I have come a long way to get where I am now, so probably shouldn't give up so easily.
So I will definitely talk to him when I can meet him in person, and make a team decision as soon as possible.
Thank you all again for your kind advice! I would still appreciate further discussion/ideas. It looks like this is a common issue so I hope this thread can help other people with their decision as well!