I'm not going to invite my best friend to an event thrown by the dick she loves
Why would you do that?
I had a bad experience with him and I had to tell her about what he did to me, and she thinks it is unreasonable and not worthy of thinking about anymore.
You should sit down and discuss with your best friend what their lover did to you. Make sure you give them a chance to understand why you're not comfortable with their boyfriend.
You're just like my bestie, I didn't want to listen and I only care about my own feelings, I don't know, that's the kind of friends I have, you don't need to know how I feel about it.
I know it's hard to talk about but she won't understand why you're this way unless you're being completely honest with her.