Our relationship *warning lots of reading but I need help*

We have known each other for the past four and a half years. I fought for his attention and told him all the time I wanted to be with him and we finally got together then a week later I kissed another guy. We broke up, I moved 30 minutes away, lost my virginity to someone else, we talk again and get back together then he kisses another girl and leaves me for her. We didn't talk for more months, I slept with other people, we talked again and decided to wait a little longer, then got back together. Everything was okay except he was ignoring me because he was playing gigs and going to parties. I talked to an ex but I have no interest in anything romantic with him anymore. Everything was okay for a few months then I get drunk with my best friend and cheat on him with my best friend a couple days before our 6 month anniversary. He stayed with me for two more months then we broke up. I slept with a couple other people. He dated and slept with a couple other girls. We talked and didn't get back together officially but he called me his girlfriend to everyone. We argue about the past so much that we stop talking for more months. He gets hammered and snorts pills and I was worried so I took care of him that night and we started talking again. We still argue about the past and what I've done but we still stay together. I get pregnant in August of 2016, the night I told him he fell to the ground crying saying he didn't want me to be the mother of his first child. For a week or two we talked about me getting an abortion because he said it would ruin our lives. I chose to keep her. We separated in November, he found some girl and I dated this guy. I had sex with the guy (which I know is disrespectful and wrong to do while pregnant with someone else's child growing inside you) he also had sex with the girl he was with. In January 2017 the girl he was with cheated on him and I broke up with the guy I was with because I was 24/7 thinking about my ex and the father of my child. So my ex and I talk and we get back together at the end of January. We still argue about the past and everything I've done wrong. I found out about two and a half weeks ago I had chlamydia. We didn't know who it came from but my ex was yelling and screaming at me calling me a whore and disgusting and a liar. Posting things on Facebook discreetly about me. I got it from the guy I was with in December. We argued and I was remaining calm while he was screaming and yelling at me. We didn't talk for a couple days then we argue again. I'm currently 38 weeks and 5 days today, we had an argument tonight. He was calling me childish because I deactivated my Facebook because I thought him and I needed space. I reactivated it just for him to message me calling me childish and we argued more then he blocked me.