My boyfriend's parents hate me for absolutely no reason.

So I hope this is the correct board to post this. My boyfriend's mother has not said one nice thing to me or about me since my boyfriend and I have started dating. I have never met her or his father. According to him, it has always been this way. I have 4 kids (3 from my ex husband and 1 from a failed toxic relationship after my divorce) and he has one son that he didn't know was his until last year and he is almost 3. She called me a baby popper out machine lmao (little does she know I am pregnant with her grandchild) and she acts as if she is the mother of his son instead of his grandmother. She thinks she runs the show and she has a say in who my boyfriend has his son around (she obviously has a problem with me). However, it has been approved in court that he is allowed to stay at our home his weekends. She HATES it. Now that I am pregnant (we aren't making it public until after the next custody hearing for his son in January to avoid his psycho baby mama creating issues), am I wrong for not wanting her involved in my child's life? My boyfriend can't stand his own mother because of her actions so he said he wouldn't be upset. I know shit is going to hit the fan once she finds out and I HOPE she comes at me the wrong way. My boyfriend was always the child that was left out and his sister was the pride and joy. Is anyone else in a similar situation?