Need sex advice.

I have been with my husband for 3 years, been married for 4 months.. and our sex life just went downhill. We used to have great sex, would do it everywhere, we even did like 4 rounds in a matter of 2 hours once. It was exciting but now things changed. It all started literally when we got married. He worked night shift so maybe that’s why we wouldn’t have sex as much, but 2 months ago we moved, he has a new flexible job and I’d think we would have more sex, but nope. It’s gotten so bad, we didn’t have sex for a week and 6 days once, today is a week that we haven’t had any. I’ve confronted him and I ask him why, and he says he doesn’t know. For 3 days straight I’ve been wanting to have sex, I make a move and he just doesn’t want to. He doesn’t look for me, he doesn’t kiss me or make the approach to have sex. I literally don’t know why our sex life changed so much. I’m 10 weeks pregnant and I don’t know if it’s because of that, because I gained weight, he’s used to me already, I don’t know and I lose sleep over this, it makes me think horrible things about myself. We’ve talked about this so many times and I don’t seem to get a good answer as to why he won’t have sex with me. I just need advise or has someone gone through something similar