How to cut her off

I’m trying to figure out if I should cut my mom off. Our relationship was never the best. I can never address any issues we have because she always tries to fight me. She even pulled a knife out on me when I was a teenager and kicked me out the house and told everyone in the family she would call the police on them if they took me in. She ruined my childhood in a way by forcing me to parent kids that she had. I missed a lot of school because I had to watch the kids. I could never really make friends because I had severe panic attacks, depression and I could never relate to the other kids anyways. She talks about me behind my back and thinks I don’t know. She throws my mental health and the fact that I was on meds for depression and anxiety anytime she feels like it. She just got a new boyfriend recently and I don’t like him for several valid reasons and I told her why when she asked me. I’m always respectful when he’s around though. Now she’s pregnant and she bring up the fact that I don’t like him again. And she says I just don’t like him because he got her pregnant. She knows my husband and I are going through fertility treatments and have been trying for years. That was definitely a low blow, even for her. It has nothing to do with the fact they are pregnant. I didn’t like him even before that. I just can’t believe she would say that to me when she knows how bad that would cut me. Now I want to cut her from my life, but every time I think about it I get sad. I always think about a good day we’ve had and it makes me feel guilty for wanting to cut her off. I already stopped telling her anything of importance going on in my life. I asked her several times over the years to come to counseling with me but she bullshits me every time. I don’t know where to go from here. How can I make a decision like this without feeling bad? I can’t keep doing this with her