Just looking for advice...

I’m currently 19 weeks pregnant and my partner shows no interest in me in any sexual or intimate way- he doesn’t even seem attracted to me. We don’t have sex except maybe once a month (if I’m lucky) and it’s more of just necessity for him. What kills me is I’ve never been in a relationship where the other person has been attracted to me. My ex used to put me down constantly and tell me that I disgusted him. This left my self esteem so low that I feel like I need some kind of reassurance to be happy or content. My boyfriend knows this and used to make me feel like he was attracted to me. He used to WANT me.Our current relationship is great. We’re best friends and I’m happy with him other than the fact that I feel like I’m not enough. I don’t know if it’s because I’m pregnant or if that’s the only reason he sticks around. He’s told me that he wants to be with me for the rest of his life already has plans to make me his wife and have a family with me. But how is that ever going to work if he doesn’t want anything to do with me in any intimate way? And how will it ever get better? It’s not like after he watches me push our baby out that he’ll finally find me sexy. That’s not sexy. This topic is just really hard for me to approach him about. I’ve already had to confront him about our sexlife once before, because we were having a lot of sex, it just wasn’t sex I was enjoying. It was honestly just emotionless and physically painful for me because at that point his only goal was for him to get off. It didn’t matter to him then if I was actually enjoying myself or even wet enough to not be in pain. Since then it improved, but then just stopped all together. I don’t know how to approach this issue at all. I don’t know how to bring up this conversation without me breaking down and essentially just asking him what’s wrong with me, like why can’t he be with me in that way. How can I bring this up in a conversation like how do I even approach this topic like “hey can we talk about the fact that you aren’t attracted to me and why that is because it keeps me up at night and I cry while you’re in bed next to me, snoring away” I just don’t know what to do.