Me female 42 told my bestfriends male 42 girlfriend that he was cheating on her. Back story I've been bestfriends with we will call him JA for 25 years. JA has always tried to get on me. JA had made sure to let me and our other friends know he was no longer with his girl friend and they just live in the same house due to him n her having a kid. She had also said that they don't even sleep together. So after years of JA pushing and pushing, I finally gave in and we slept together. And it happen weekly for a couple years. He had started treating me differently and I found out JA was definitely still in a relationship with her. So I decided to tell his girlfriend what had been going on between JA and myself. And that he had been lying to me the whole time too. Felt like she deserved to know. JA was mad at me for telling her.... jA acts like I'm in the wrong and somehow did this to him. Not sorry for lying to her or I. I can't figure out how I got the blame for his relationship ending when he did this to her and I. So am I the asshole for telling my bestfriends girlfriend he was cheating on her?