marriage ending

My husband has screamed at and kicked my mother out of our home twice now. He blames her for our marriage issues, saying she is toxic and makes me choose between her and him. My mom has done some rude things (mostly to do with his parents, not saying hello and being anti-social) and definitely hasn't helped anything but it's more his reactions that worry me.

Two nights ago he yelled and screamed at me after the incident of my mom and gave me the ultimatum of choosing him or her. I wouldn't do that so he said we would be getting a divorce. The yelling and screaming happened in front of my sisters who were all afraid for me. They thought he was going to hit me (which he has never done). We ended on him saying we are getting divorced because I wouldn't say that he was 100% right about my mom and that I wasn't backing him up as his wife. We slept in separate rooms.

Next morning he continued to refuse to back down about the divorce until he talked to his brother. Now I have said I will be on his side, address the issues with my mom but I feel empty. Like nothing towards him and he doesn't see his part of the behavior as a problem. I asked him to go to counseling and he originally said yes but has backtracked on that as well, saying he already has the tools to make a marriage work because his parents have been together since high school. I just don't know if I actually want to be married to him anymore. It certainly isn't what I thought would be happening right now with my newborn son.

I am just lost and could use any advice, words of wisdom or hang in there's...

Edit: my mom was here to help with the baby and was helping me a lot. The 2nd time she was holding the baby so I could take a good nap. She is not living with us, just visiting.

Update: my husband has agreed to counseling, thank you for your input and advice!