Why cant my boyfriend cum?

My boyfriend and I have been together for about 6 months, he doesn't initiate sex or even really talk about it. I absolutely love being intimate with him and I feel like that's the only reason it ever happens. When we do have sex, I seem to cum very quickly, which is very new to me as it's never happened before, but now I cant get him to cum. I try oral, sex, teasing, everything. I feel as if he's losing attraction for me.