What Can I Do?

I wanted to post this in the mens forum for a man's perspective on this...
My boyfriend and I have a pretty active sex life. He is almost always horny. He gets extremely stressed out sometimes and depressed and he can't come, but I understand that it has nothing to do with me. But the other night he didn't finish and said he was too tired to finish. Now sometimes he makes comments like that, like he's trying to throw hints to me, that I don't do enough "work" when we're having sex. I almost always give him oral (he never gives me oral) and he usually wants to be on top or go at it from behind...And if I try to move with him he gets mad because I "throw off his rhythm"...Lol. So I don't know what to do for him! I don't want him to "always do the work" but he doesn't like when i'm on top. Any comments or suggestions?