I HATE my MIL

My s.o and I have been together for 12 years now. For that amount of time his mother has been completely rude towards me and has never tried to hide the fact that she doesn't like me. For that reason we have kept our distance from not only her but his equally rude family. Because of the way she's been towards me I have grown to despise her. I can't stand her. Everything she does and says boils my blood. Well recently I have given birth to our first child. Because of that I have been forced to involve her. She decided that she didn't like the name I chose for my son and proceeded to calk him by my s.o name. She asked my husband if he had any say in the name. She even acted very surprised knowing I gave my son his last name, thinking my son would take mine. Today she called and very rudely asked to speak to my s.o. She wanted me to take my 3 week old son and leave him alone with her because I don't stay long enough to her liking and because, I'm guessing she doesn't want me around. I will never leave my son alone with her. Ever. Especially at 3 weeks old. I'm done dealing with negative people who I've done nothing wrong to ever and I've decided to separate from his family again, including my son.