Sex While Pregnant

I am seven weeks and three days today with my husband and i's first child. Does anyone else have a difficult time with sex while pregnant? Not only am I not orgasming, but it's pretty uncomfortable too. My husband seems to think I'm making it all up or am choosing to voluntarily not wanting to have sex with him. The drive is there, is just not able to enjoy it like I was beforehand. I just don't want it to get out of hand to the point where it puts a strain on our marriage.