That's so true. First time it happened to me I got mad. My then gf and I had an argument at a disco and I left. I waited outside because I assumed she was coming out after me. She didn't. So I went in again and found her dancing with a guy, rubbing her ass on his crotch. I was mad but couldn't stop watching while hiding. When they went out I followed them, they got inside his car and he fucked her there. I could not see much as I was looking from some distance, but they were obviously fucking. I did not know what to do and went home convinced I would never talk to her again. A couple of days later she called me and asked me to pick her up at her house. I thought I had to go just to hear a ridiculous excuse and then tell her what a slut she was. But she came into my car, kissed me and smiling told me she hado to confess she had had sex with another guy, and if I really loved her and wanted to forgive her, she would never do that again. I couldn't believe she was actually being honest and cheeky, but I swallowed my pride and accepted. No need to say that she cheated on me many times after that. She would fuck just any guy she found attractive and tell me that she still loved me but she couldn't help it. The thing is that I started to realize that I loved her to be like that. The problem is that everybody knew it, all our friends did. She even fucked two of my best friends.