Friends bf cheated & she’s mad at me

My BFF found out her bf had been cheating on her since the beginning of their relationship. She found a bunch of stuff on his phone when he came home drunk & right when she had his phone a girl called him to check if he got hoke alright. She called me right away & I told her to tell him to leave. Well instead he somehow made her think she was crazy & they had sex.

I told her I didn’t get a good vibe from him when she introduced me to him. Main part of it was that he was flirting with everyone (even me). & he told her to keep the relationship on the down low because they work together. Well to my main point… she is upset at me. ME!!! She called me 2 nights in a row after the first time to cry about him & how she didn’t trust him. I told her if she didn’t trust him, it wasn’t going to work between them. She yelled at me saying I was the cause of them breaking up because I got into her head?? All I told her was she didn’t deserve to be treated that way & that he was a clown who gave her an std . I’ve backed off but idk what to do now…