Not actually me who cheated in this, as it was my friend, but I thought it was so hot I had to put it.
Basically went out last week with my friend (who has a boyfriend) and we got pulled by two hot guys who lived together. We thought fuck it. I felt like getting fucked and I knew my friend had cheated on her boyfriend at least twice so we went back to theirs and into each of their rooms.

Even while I was getting done, I could hear my friend getting done pretty hard. It made me come even harder than normal, hearing her cheat in the next room- the bedsprings, the slaps of flesh on flesh, her moaning and screaming.

The next morning, as we rose, I passed their room on the way to the bathroom and saw their door was half open. She was dressed and ready to leave, but on her knees giving her guy a final blowjob. It got me SO hot. I went back to my guy and asked if he wanted one, but he just chuckled and said that he just drained himself into me when we fucked when we just woke up, which was true I guess.

So I went back quietly to watch my friend on her knees. I reached into my panties (a little wet with my guy's cum) and fingered myself as I watched. I saw as he came, still in her mouth, and heard her gulp it all down.
The hottest thing was that I knew she was meeting her boyfriend in half an hour to go shopping and would probably be kissing him.

I texted her later asking if she enjoyed giving her boyfriend his 'special kiss'. She just replied 'ha yeah. not the first he's had anyway lol'