Blow jobs?!

Ladies, I was wondering if this happens to any of you as well as I. Almost every time after my boyfriend and I have sex he wants a blow job, and me who likes giving them to him because he goes wild does it. But my question is, if my boyfriend wants a blow job almost every time does that mean he didn't cum while we were having actual intercourse? And if so how do I make it so that he does cum during intercourse I don't want to be the only one getting off during intercourse.