Best Friend Issues

Call me Rachelle
Okay my BFF has had a friend with benefits for a few months now. In the mean time she had sex with some other guy and was honest with the original FWB about it. He didn't care and continued on as normal. However, after he had sex with another girl she flipped out and got real mad at him. Isn't this being a bit hypocritical? since she did the same thing and it's not like these 2 were in a committed relationship. It had no title to it. And when single u can technically do whatever u want with whoever. She just got mad since she felt it was revenge, and has a big ego. Heck not all people r even honest about this kinda stuff anyway so u gotta give props for honesty