My BF of 2 years left his FB open on my phone. We are both completely open with our social media and I have trusted him but always been a bit 
about his attitude to his exes. His friends are mainly his exes, which I have been fine with but they, and him, have tried to make me start a friendship with them. And they are all friends (3 of them) too 
. I am totally not interested in that. We are a bunch of 30 something's and I don't have anything in common with them. They are all child free and single and I have a FT job and 3 DC's so in my free time the last thing I want to do is hang out with my bf harem of ex girlfriends thanks 
His main ex, who he was with for years, tried to befriend me at the start but I gave her short shrift. I think it's weird.
So, a message thread keeps popping up on my messenger from his most recent ex, this one he was with for less than a year. When we got together this ex wasn't very nice to me (said some awful stuff about my mental health because she had info on some childhood trauma I've experienced ) and deleted my boyfriend in a flounce. But obviously got over this and recently they are friends again.
So in this message she said 'I'm having a get together. You are welcome to bring Gertrude and her DC's. Other Ex will be there too' and my boyfriend messaged back:
'Thanks for the invite but don't think Gert would be up for that. Some people aren't good with ex's. You know how it is.'
AIBU to be a bit fucked off with his response. He is free to have whatever relationship he wants with his friends but the way I read it, it's making out that I'm BU to not want to go have a cosy afternoon with my DC's and them.
I haven't said anything to him about it but would you be too? Or am I overthinking it? I do have a propensity to do that.