As far as i can see you are a single mum already!! Dont ever sell yourself short for anyone! And dont stay with him for the kids sake as it will have a negative effect on your kids..
I dont know the ins and outs, but it sounds like you want to leave him but your scared. Never be scared.
I was in a domestic violence relationship with my ex (father of my girls) and put up with abuse for the sake of my daughter. It was too late by the time i figured out it was affecting her. She has issues big time now

It took something big for me to realise what was going on. He let my youngest choke on her sick at 5 weeks old. the look on his face.. cold. willing her to just give up. she was purple and not breathing in my arms and he was fully trained in first aid. he picked up my eldest and left the room while i was screaming for help... he came back and threw me a leaflet on choking. it was then that i realised it had to stop.
Physical, mental and emotional abuse are all the same in my book. i was unfortunate to get all three in one hit. What you are going through is wrong.. but you seem to have a very loving family that im sure will support you while you get on your feet if you decide to leave.
I dont know the full story so im in no position to say leave, but definitly think about what is best for you and your children. Dont let him treat you this way. He has no right.
Im sorry for ranting but i have strong feelings on these subjects... please feel free to PM me at any time if u want to talk.. im always here..
I hope you find the strength to keep on being the fantastic mother you are and never let anyone make you think any different. You are worth more!
God im welling up.. damn hormones..

Please do something, you cant keep living like that. Relationship councilling? Anything!
Dont ever think you are overreacting to a comment like that!!
I used to make excuses for him and find a way to believe it was my fault and i provoked it etc etc... no.. thats wrong.
((((HUGS))))