I found out my (ex) partner's best friend was a 22 year old virgin. I couldn't resist. After a couple months of hooking up, I ran into him at my partner's house. He wore no shirt, showing off MY scratch marks. I was livid. The next week, he knew my partner planned to surprise me at my dorm and he came over just before. We were nearly caught and I was tired of his stupidity. My partner later found us out through a photo I took of the friend driving my car. I "accidentally" left it on my phone. The friend was terrified of my partner, and rightfully so! He was a brute of a man.
I convinced him to tell my partner and all their mutual friends that he was a faggot, the scratch marks were from a guy I knew, and I was the cover. I told him I knew a guy who would even pretend for us, that way he could keep his friends and I could keep my partner. They proceeded to text each other and swap photos. Meanwhile, I told my partner and their mutuals that the friend talked me into fooling around with him when I was drunk and later blackmailed me into continuing the hook ups. The friend showed up at a mutual's house to see my partner, readied with the gay sexting as proof of our innocence. My partner told him he'd only accept a written apology/confession, read aloud on video. The friend agreed to read the apology in front of their buddies. I gather they didn't actually record as about halfway through they kicked in his shit.
I stopped fucking with any of them, but man was that amusing.