Is this normal?

My husband and I have always been pretty sexually active during my pregnancy up until probably 3 weeks ago. (I’m 33 weeks now) I don’t know what happened but all of a sudden he wants nothing to do with it but, I’m craving it more than ever. I’m not sure what’s happening but I do everything to try to get him to want to and NOTHING. It’s gotten to the point where I’ve been making myself go crazy thinking what if he’s cheating on me. Is anyone else’s husbands been like this or should I be worried? I wanted to see what everyone else says before I bring it up to him that it’s upsetting me.