My ex- boyfriend went back to his country for a month and half while we were dating, and our relationship, in my opinion, never got past that awkward emotional distance you mentioned. We broke up a few months after that. That you and your boyfriend have successfully recovered, with him still being supportive enough to let you go yet again for longer, proves you have a very strong connection. Plus, chances are, even after this one, more opportunities may come up. Soldiers leave for years at a time, and as far as I know, their families usually do not desert them for leaving to work for something they believe in. If you want to have a successful long term relationship, any partner you have will have to accept that these projects are a part of who you are, and a part of the whole package. And, if you've found a man that says he accepts that, and with whom you have such a enduring relationship with, then I'd say. . . accept that he knows what he's saying when he supports you. While 5 months is a long time, its not forever. If you dont let it get awkward and you control that emotional distance before it gets out of hand, you'll both allow yourselves to just be glad to be back together.