I'm so sorry you went through that.
Your feeling bad for the anger you understandably feel towards your mum is natural & also because you're a kind empathetic person who wouldn't have done what she did but that anger doesn't make you a bad person. You had an abusive childhood & it can take years to come to terms with everything you went through. It's also possible there's some anger because she's passed on so you can't talk to her about it or confront her. Her choices hurt you & that's on her, not you. Sounds like she was a victim unaware of her patterns in choosing abusive partners but that doesn't excuse her for allowing her choices to harm you when she should have protected you.
I hope you have love, support & good people in your life now? Hugs,
xxx