Friends with Benefits?

So I've been sleeping with a friend of mine since December, and it's, frankly, the best sex of my life. Hours on end and endless orgasms (tmi? 🙈)   He's phenomenal and he has the potential of being an awesome boyfriend. However, he got out of a long relationship 4 months ago and we are in extensive Air Force pilot training so we've talked about not being together and staying focused on what's important right now. We don't really talk during the week (class and studying and flying), but on the weekends it's like we've never been apart. He says things like "you're amazing, how did we not see this sooner" and "this just really works, doesn't it?" So I feel like he understands, but is he just using me? Would I be silly for ruining a good thing if I tell him I can't do this anymore? I really like spending the weekends with him and I thought I could keep emotions at bay because we are so busy but not with the way we are together. I want someone to care about me! I'd love some unbiased and outsider advice.