Would you want to?

So I used to hangout with this group of friends in high school, I lost touch with most of them when we all went to college. I still talk to one of them, who still talks to one girl in particular. They were close in middle school before the group was created, so I’m not surprised they still talk. This other girl, let’s call her J. J and my kids’ dad got together while we were broken up, I don’t hold that against her, she barely knew him. (We got together in hs so she met him a few times). But, quite a few years went by, so it’s fair if they didn’t recognize each other. They weren’t together long before he ended it with her to get back with me. He didn’t cheat on her with me or anything, he just decided he wanted his family back. When he started talking to me about how to fix his mistakes (the original reasons we broke up), she started texting him, me, his parents, his grandparents, everyone she could think of trying to convince all of them it was terrible for him to get back with me. This is what I hold against her. And her telling him she would be his side piece and I never had to know. Of course he told me himself. Fast forward a year since all that and here we are. My friend asked me if I would go away for a weekend with her and J (bachelorette party is my assumption bc I know she’s getting married but she hasn’t actually specified that yet). Am I wrong for not wanting to hangout just the three of us? Like if there were more people, I could avoid her. But I can’t. So no. I don’t want to be around her.

(For reference, we graduated high school 6 years ago)