I don't know what to do!!!

My boyfriend(all of our friends and family refer to us as husband and wife, and we've mutually agreed that we don't wanna get married because it's just paper and the money we would put towards a wedding we could save to travel which we love to do together and share with our kids) of 9+ years hasn't been acting like him self. We have 3 kids together I have helped raise his daughter from before we met who's now 12. We lost our 1st in 2015 she was stillborn and then we had 2nd in 2018 then had our 3rd in 2020. The Dr told me when our 3rd was a yr and a half that having another baby was very unlikely. We took this as a sign and decided we were done and planned his vasectomy. About a month after it was scheduled we found out I was pregnant with our 4th. He said he didn't want another but he knows my personal views on abortion and if theres no risk to my life and the baby is healthy then I personally can't morally do it. He was fine and eventually what thought accepted we were get blessed with another baby. Well now I'm 26weeks pregnant and for the last week and a half he hasn't been acting like him self. He won't touch me he won't look at me. He ignores me and acts like I don't exist! He's messaging some girl he had a fling with years ago(he thinks I don't know about the messages between him and this girl but I do I have screenshots of them all) plus she knows we are expecting our 4th child together. And he says he has regrets and everything is one sided...he's not 16 and this is his first child...he knows how sex works????? I ask him if he still loves me and he says he doesn't hate me. He also is going to the bar every night and getting drunk. He's normally a very present father and 'husband' and it's like he just checked out!

The whole thing stresses me out I don't eat I barely sleep. I cry all the time.

And no I can't just leave, I'm a stay at home mom so I have no job, no money. We have one car and he takes it to work each day. And I have no sitter for the kids. No I have no family to help me leave either! My parents both died before I graduated highschool, both parents were only children so I have no aunts or uncles, both my mom's parents and my dads parents have both passed away too. I have siblings but they love to far away to help or they work touch to have a social life.

I tried talking to his parents and they have nothing to say. Basically the only people who are just as concerned as me are our close friends we consider extended family.

I don't know what to do love him and I don't understand where all of this is coming from it seems so random and I'm just really worried about him!!!