Just celebrated my 4-year anniversary with my girlfriend(dating, not marriage). I think it can work if you are really right for eachother. That doesn't mean it will be easy, and you see many people break up in grad school. Although often times people "blame" grad school (or med school, law school, etc.) my personal belief is that these relationships probably wouldn't have lasted anyways. The best trick I've learned so far is maintaining independence. Grad school can be stressful at times and if you "dump" stress on eachother, that's going to be a huge problem. If you rely too much on them for the things you don't feel like you have time for (housekeeping, cooking, etc.), they will end up resenting you. If you are chronically stressed, you might be resentful of them if they are stressed and try to talk to you. If they rely too much on you for doing "fun" things (i.e. won't go anywhere unless you go too, no friends outside of the relationship), they will end up resenting you for being unavailable. This will add to your stress and you'll get resentful of them for not being understanding. Obviously one of the great things about relationships is having someone who is supportive. However I think some people push it too far and forget that a healthy relationship is two functional people who become better when together, not two people who need eachother to be functional. I actually think its true of many relationships in general and a recipe for future unhappiness, but grad school seems to highlight this in many cases. Don't know if that helps or not. Its not easy but I think its doable.