Is OTHER wrong in the post ? POST : I have a friend that I enjoy being with, let's name her K, and I have known her for longer that my current gf, we had casual sex once half a year ago and that didn't affect our relationship, but we agreed to not doing it again. 
My current gf had a disagreement with K and she hates her now, and K kind of stopped talking to me since that problem, but today I had the opportunity to fix things with K, and we are friends again, we took a group photo with her and two of other friends, she uploaded it to his insta story. Not even 10 minutes later I receive a message from my gf, who is now mad because I talked to her.
She now wants me to stop talking to K completely, even tho she knew K and I where friends before I even met her.
So, AITA? 