Relationship question

My boyfriend and I have been together for almost two years, and up until a little over a month ago, he was asking to have a baby.. which we had been actively trying for about 6 months.. having sex very regularly, not every day but just about.. but recently, we haven’t been having sex, and he hasn’t even mentioned having a baby.. I don’t know if I should think he’s cheating, or what to think.. when I’ve asked him what’s up, he acts like I’m overreacting.. what do you all think??