Baby daddy cheating while I’m pregnant

I know this happens quite often when your young and have kids.. but I truly feel so stupid and regret keeping my pregnancy. I got pregnant beginning of August and it was a shock enough that I was pregnant we had been using protection. First thing I did was schedule an ultrasound at this clinic. And then I found out I was 8 week’s pregnant with fraternal twins. We both made a decision right then and there to step up and make something work. He said he would stop smoking weed and work hard and support me and the kids. I would have worked as well but I’m behind in school and I need to graduate high school, everyone agreed I needed to stay in school. Anyways, months go by and he keeps telling me we have a couple thousand saved up. His job pays 20 an hour. Then one day I found out he’s cheating, spent all the money we had saved up, and is missing work often. We start going through hard times, his car keeps breaking down and we can’t afford to buy a new one because he spent all the money he had saved up. I continue to find him on dating apps. Then recently he admits he had sex with another girl. That was a couple days ago. He keeps saying I deserved it cause I cheated on him 4 years ago. He also recently got fired for his job and I’m due in a few days now. I’m in so much pain psychically from the pregnancy I barely sleep at night. He admits to missing a lot of work to meet up with girls. The reason they fired him was because of attendance and now he’s smoking more weed then ever. And now he’s acting like nothing is about to change. He keeps texting girls, smoking weed, and enjoying himself happier than ever.