I'm so sorry.
It sounds like you were hurt by one man when you were a child, then another came along and realised here was someone damaged he could dominate - and added his own abuse. They can sniff this out and are attracted to it.
How old were you when he arrived? Very young, I'd imagine.
Stepfather? It reads as though your mind has instantly gone to a place where your own story gets played out again as something inevitable. A vicious circle.
A stepfather for your child isn't the inevitable step.
In fact I think you'd be better off single.
Finding yourself, allowing your intelligent, loving, educated self to emerge from under the weight of two abusive insulting damaging coercive controllers.
And building yourself up into a more resilient self confident independent woman and mother.
Therapy might be possible and helpful for you.
The freedom programme and women's aid have already been recommended.
Consult a solicitor to find out your rights.
Do you have anyone else? Parents, siblings, friends? If he might have alienated and separated you from your network, it would be wise to reach out and start reconnecting.
So many women here still cope with the legacy of abusive fathers and mothers who did not have the strength to leave - and protect them. And so many others are grateful that their mothers did.
He's going to be doing this to your child too.
And one day when your child has moved away, possibly limiting contact with you, there you'll be, an unpaid youngish nurse to a vicious old sod.
I hope we're helping you think this through?