I (24F) had a relationship with my ex for 3 years that was horrible. He was emotionally abusive, constantly put me down, and isolated me from friends. There were also a few incidents where he got physical - pushing me against walls when angry or grabbing my arms so hard they bruised. I finally got out of that relationship 6 months ago. It was the hardest thing I've ever done. I've been in therapy since and slowly rebuilding my life.Last weekend, I discovered my sister (26F) has been secretly dating my ex for the past month. She claims she "didn't know the full story" of our breakup (BS - I cried to her for hours about it). She says he's "changed" and that I'm being dramatic about what happened.When i confronted her, she said I was being selfish for not wanting her to be happy. She actually said, "You're just jealous I'm getting the better version of him that you couldn't keep."I completely lost it. I told her she was dead to me and blocked her on everything. My parents think I'm overreacting and should "be the bigger person" since "family is forever." They don't understand how triggering this is for me - I've been having panic attacks since finding out.I feel like my sister betrayed me in the worst possible way. She knows what he did to me, yet chose him anyway. But now I'm getting messages from extended family saying I'm tearing the family apart over "petty relationship drama."

So AITA for cutting my sister off for dating my abusive ex?