Dated awalt bitch for 1.5 years in that time i briefly introduced her to my group of male friends e.g a few nights out at local bar. Once i saw her true colours after the honeymoon period i knew she wasn't going to change and i intiated the break up, after a month of no contact i agreed to just be friends out of convience knowing full well i would avoid all contact. Recently found out from a friend of a friend that she and my group of friends have gone for drinks togheter and chatting shit behind my back(i can handle some male banter and shit talking when it comes from a place of comradery not malice). My suspicions were confirmed when i heard she started a group chat without me and also when a friend from the group referenced an inside joke in our relationship.She is not below this kind of behaviour and i know my friends are happy to have a "cool girl" in the group.
How do i handle this without seeming weak and bitchy? I have already invested a solid few years into this group and will not be edged out by this miserable cunt.