The relationship between my ex and my immediate family makes me feel extremely uncomfortable

Hi everyone, I just need to get this off my chest. I’m sorry if this seems a bit long, but I need some advice. Two weeks ago, my girlfriend (20F) of three years broke up with me (20M). It wasn’t a big drama. Without going into details, she didn’t want to fight for our relationship anymore and preferred to give up, neither of us was really at fault.

It destroyed me, especially since she left me when I needed her help the most and I’d been carrying her on my back for two years while she worked her way out of her depression. But hey, I can’t force her to fight for us or love me, just as I can’t possibly blame her for choosing herself.

I think it was too hard for her to accept her decision, so instead of leaving on good terms, she decided to do things differently. She made me out to be the sole monster responsible for the end of the relationship; she decided to destroy me by insulting me for hours on end and using my deepest insecurities against me. After she left, she kept trying to control what I was doing through mutual friends. Just as I was starting to grieve, she came back begging me to take her back, telling me we’d fight for each other. I agreed; I trusted her again, only for her to break up with me a second time a few days later because, according to her, I was asking for love and security but was supposed to show her that I was worthy of her time.

I was stunned by this woman who seemed like a stranger, and I had to start the grieving process all over again. By the time we were returning our belongings to each other, we hadn’t completely cut ties yet. She took the opportunity to break the no-contact rule and call me again, crying. I refused to trust her again, but out of respect I listened to her. What had started as a call of regret or perhaps an apology turned out to be a way to test the waters. She quickly told me she’d called because she was having doubts, but hearing my voice reassured her in her choice that her whole family, her friends, and she herself thought I was a jerk, and that she was infinitely happier now and was seeing other guys who were there for her.

After that call and all that childish behavior, I tried to save face and move on, but by the end of the week I was completely wiped out and devastated. We returned each other’s belongings and finally cut ties, but I found out she had the nerve to contact my mom to attend an intimate family dinner where all my loved ones were gathered. I managed to veto it, but she keeps trying to meddle in my family’s life, especially through my sister.

I know my sister and my ex are both adults and that it’s not my place to interfere, but part of me is completely losing it. I think it’s so damn selfish of her. She knows this is preventing me from grieving, and even though she deliberately destroyed me, she’s throwing parties with my little girl in the house where I grew up. Maybe I have a problem, maybe it shouldn’t affect me i don’t know. In any case, I’ve decided to take the plunge and open up to my mom, especially about the pain I’m feeling right now and how this constant interaction with my family is preventing me from grieving.

My own mother just refused to take sides between me and a woman she’s known for two years. I have to admit I feel TERRIBLY alone, and I can’t even count on my closest circle of friends to be there for me first and foremost.

I don’t know what to do; I feel completely helpless.

TL;DR : My ex keeps spending time with my family even though she deliberately broke my heart, and that makes it extremely difficult for me to move on Even though it doesn't give me confidence in my relationship with my family