Relationship issues

I will try to keep it short but I would like some advice. My boyfriend and I have had problems lately but I don’t know how to fix it. I had a girlfriend for years that had gotten close to my boyfriend and was crossing boundaries. She would hang out with him solo and I caught her with her legs draped over him while we were all trying to watch a movie among many other things. I told my boyfriend how I felt and how insecure it was making me feel and somehow she found out (I had only told my mom and boyfriend at the time) There was a big blow up at me and she cut me out of her life before I really had a chance to truly talk to her. We had a large friend group and we did lots together and now I have been isolated. My boyfriend still goes without me like nothing has changed. I have vocalized my concerns and how my emotions are being affected but the information doesn’t seem to stick. Sometime I think he likes the attention from this ex friend of mine and he doesn’t want to change any hangouts with the group for my sake. It’s really frustrating that everyone is okay with what happened. I’m the bad guy now and I didn’t even have an opportunity to speak my piece with everyone because I have been kicked out of the group by one person. I feel so isolated and no one cares to listen.