Advice Needed

I used to date this boy. We were in like a group of friends but now one of those friends is dating him. I really do like hanging out with that friend but when we started hanging out more I also got closer with the boy. Stuff happened and now she basically hates me and I don’t talk to the boy much anymore even though we were comfortable being close friends. Basically the girl is convinced I’m trying to get the boy and says that I only got closer with her again to be closer to him. She also doesn’t let him talk to me anymore and rants about it on her Instagram story. So now ever time I do try to talk or text the boy he tells his girlfriend and everything starts all over again. She just pisses me off. I don’t know what to do because I want to be able to still be friends with the boy.