Short Term Relationships

The interesting thing about knowing I'm going to be leaving here in less than three months is that I find myself attracted to a lot more of the guys here. And I think it's because (for better or worse) I'm not thinking in terms of long term relationships, but just in terms of: "Hey, he seems like a good guy. I could probably have some fun being in a 3 month relationship with him, enjoy the affection, and learn some things." And when it's just for a few months, I feel like I don't really have any hard and fast standards or anything.
But I don't know if I could actually do that--like, just have a relationship that I knew wasn't going anywhere. I feel like for me to really invest, I can't know for sure that it's going to end really soon. And I can't decide if that's a good thing or a bad thing.
I have some friends that are like--hey just have fun, learn, love, be loved, it's all good. And some friends that think it's better not to get involved with someone you know you couldn't be serious about. I think I'm more of the latter, but maybe I need more of the former in me. I dunno.