Mother in law of terror

My husband and I are expecting twin boys and I am currently 22 weeks along. We have been discussing who is going to be in the room if we deliver naturally. I said that I want it to be just him and myself. He then brought up that his mom wants to be in the room. I told him that if she thinks that she is going to be in the room, she's crazy. We invited his parents over for dinner tonight and sat down with them and told them what we wanted. Mil went absolutely nuts. She said such awful things directly towards me. She told me that a b**** like me doesn't deserve someone as good as her son right in front of everyone and as she was walking out the door she said that she is going to be in the room whether I like it or not. During this time my father in law kept apologizing for her behavior and I feel bad for him because he's such a sweet gentleman who doesn't mind staying in the waiting room. She still hasn't stopped either. She's messaging both my hubby and myself. She keeps sending me rude messages and she even is lying to my hubby and saying that I'm the one who is lying and that he should leave me for his ex who mistreated him. If she causes any more problems, she will never be involved in my children's lives. I'm just crying and my hubby is here with me and supporting me through this war between his mother and I.