I was with my wife at her friends house. her friend has been single for years. I'm 26 and their both 28. that day there was a problem at my wife's work with a receipt machine so she went over there to figure it out and I told her I'll stay behind. so she left and said it would take no more than an hour. her friend was quick and asked if I'd tell her what I think about her new clothes. 

I said yes. while she was showing me she would purposely change outfits and let her tits out and walk around in her underwear to make me look. no time passed at all and I was on top of her in her bed fucking her hard. we even ended on the bathroom sink at one point. 

I came inside her and pulled out and got dressed. I felt kind of bad but at the same time I always wanted to fuck her friend. we never had sex again after that but she does text me sometimes hinting at it. I'll get her again one day

Source: Confessions