My mother wants me to choose between her and my partner

My whole life my parents have been very strict and disapproving of basically any choice they didn’t make for me. They’ve destroyed relationships with people I cared about, and I think my mother is trying to do it again. She’s decided she hates my partner of nearly three years and that she can’t stand to be around them. Every time their name comes up, she’s mad the rest of the day. She refuses to say that anything is wrong, but growing up with her I’m fluent in passive aggressive. I’m legally an adult, but I’ve never been allowed to make my own decisions so I still feel like a child. I still seek my parents approval in everything even though I know I’ll never get it. My partner and I are moving in together soon, and my mother has been turning up her hatred of them. She takes every mention of them as an invitation to tell me that they’ll ruin my life and hold me back and eventually I’ll hate them, but she makes no effort to get to know them or change her mind at all. Even though she never says it, I know she wants me to choose her over them. Every time I’ve brought it up she’s denied it, and says she just wants what’s best for me, but that’s the same thing she said when she locked me in a mental hospital and took a restraining order out on the last person I loved. In an ideal world I’d go no contact with her and be done, but the rest of my family on that side is supportive of my decisions in life and I can’t imagine not having that branch of support system. If I cut her off she’d find a way to paint me as the villain so they never spoke to me again. Has anyone ever dealt with something like this? I’d love some advice or stories about how your situation turned out or literally anything to make me feel like it’s not just me being stupid and immature and making my own personal hell