My ex and I were together for 3 years and the last year of our relationship she was sleeping with her gym buddy. I only found out because one of my friends was at the gym and over heard them talking about it. I confronted her, she confessed and we ended things. It wasn't a pretty break up, she lied to a bunch of my friends and ended up stealing them. 

This all went down 5 months ago, I heard through a friend of mine that she started dating a new guy. After some searching I found this guys info and sent him an email saying what happened to me. I know that I would want to know if my new GF cheated on her last partner. 

He broke up with her and told her that I told him. Now she and a bunch of my ex-friends are calling me an asshole. My ex-friends don't know she cheated on me, I told them but they believe her side of the story, not mine. 