Pregnant and violent stepdad

So my mum has been with a guy since I was little that’s always been violent towards her but never me up until 2 years ago when he strangled me. I moved out and now I’m constantly stepping on egg shells not to set him off incase he’s violent towards my mum.

But I’ve just found out I’m pregnant. I’m 22 next month and haven’t been with my partner for very long and am so so scared on how it’s going to turn out. I’ll tell my mum first without him so we can figure out how we will tell him but I’m scared for her! She’s going to get the worst end of it and then if I’m there when he finds out is he going to hurt me even though I’m pregnant?

I’m so so happy that I’m pregnant and then i think about him finding out and I just end up crying!

Any advice is welcome, thank you.