Hello 
Eerily, I could have written that exact post 12 years ago. I left him when I was six months pregnant - when I realised what a total twat he was.
Do you have a supportive family? My parents were wonderful, but I still brought my daughter home to our own house from hospital - just the two of us.
During my pregnancy, I looked after myself, concentrated on the baby and ate well - she was 8lbs4oz, the birth was ‘easy’ and she took to breastfeeding so easily too. She’s now 11, hilarious, compassionate and considered gifted (I include this as people tend to be so judgemental when they see a 20 year old pregnant, expecting the worst life imaginable for their child)
Forget him, look after you. Consider breastfeeding too, as if it works, it makes life so much easier when you’re by yourself.
I had difficult times with my daughter’s father but we came to an arrangement - via solicitors - where he saw her a few times a week for a few hours (in my house initially, as no bloody way was he taking her to his). The same arrangement is still in place - they both like it that way - and they just do fun things like going to the cinema etc.
He’s slowly maturing (although 35 
) but will always be what he is. He contributes to my daughter’s piano lesson - treats her to nice things and they have their own special relationship.
She has other male role models like my father who have modelled a more stable male figure for her to look up to too, but she loves her Dad, faults and all.
I wouldn’t really put up with it if I were you, but I would try to stay amicable.
If you choose to stay, give him an ultimatum; however, know that you can do it alone.
Very best of luck 