What do I do?

Long story short I got pregnant really quick after dating someone and it turns out I had no idea who he truly is. He has a 9 year old from a previous relationship(they were together 11 years.) so he lied about having a job, that he was in the middle of moving, and pretty much everything else. He drank every night but quickly turned into an all day everyday thing. By the time I had my son he was drinking from when he woke up until he went to sleep. As soon as I had my son he started being really really mean to me. Calling me every name in the book. Calling me a fat cunt the night I had my baby. I’ve been very very dumb and still stayed. He hasn’t had a job our whole relationship. Therefore he doesn’t provide for our child. He can go days without seeing our son but begs to see his other. He takes his oldest places and makes sure he’s fed. But he can’t buy diapers or formula for our child. He has cut his drinking back tremendously (that I know of.) but he’s threatening to take my kid from me and use my past against me. Is there anything I have to worry about? I have no criminal record. Thank you if you read this far....