Would this bother you?

My bf has a friend (female friend). Who hes admitted he used to fancy alot a few years ago. He says he doesnt fancy her anymore it was a long time ago, now shes completely just a friend as they get on well. They're going out for a drink together with her flat mates and maybe his flat mates too.

Hes invited me but I have a feeling I wont be able to go. Would it bother you?

I'm not entirely sure how to feel about it. He asked me if it was okay which was lovely and such a green flag, to which I said yes. He also invited me to come, to which I said I'll definitely try to!