Help deciding

Husband and I have been together for 12 years I been through hell and back cause of him.....well I'm 20 weeks pregnant I have a 5 year old and 1 year old that are his in my desperation to keep my babies father home I begged him to stay and I would do anything to save my marriage (had a fight with him I don't talk to none of his family members cause they kind of made this big fight started and I won't talk to them not even his mother) we have been good texting and calling each other like before this stupid thing but he gave me an ultimatum if I don't go to his mothers house or call her and say I'm sorry (I haven't done shit to this lady) he won't ever come back home 😒 I told him forget it I won't not cause I don't want to talk to her I mean she is the grandmother of my kids but wtf ! You prefer to be away from your kids because I ain't talking to your mom? Should I call her or say fuck it?