Wife and Sister's Boyfriend

My wife has been very conservative and very uptight about sex. She was the type that worried that being too wild in private would somehow make her think less of herself as a teacher. So, when I told her I was interested in a MFM, she very much said NO. I had been working on her for about two years; getting her to dress sexier, get fit, and experiment more in bed when she finally said that she would do it if it felt right. It finally did and it happened. After that, her sister started dating a new guy after being divorced. One night while we were having sex, I asked her if she would do it with the boyfriend. She said no since she had a pretty firm rule against even fantasies about people in our lives. I kept after her and eventually she went along with the fantasy when we were having sex. About six months later, her parents arranged for the family to rent two houses at the ocean over Thanksgiving. The sister's new boyfriend would be there. The adults would be in one house and the teen kids in the other. One morning I got up to run and heard the boyfriend walk down the hall. I listened and it sounded like everyone else was asleep. I whispered to my wife to go out and talk to the boyfriend, tell him I was running and see where it went. She shook her head no, but I kind of begged. Finally, she gave in. She put on this pink satin rope that came down to her thighs with nothing underneath except her panties. The robe had a tendency to slip open which is why it was only used for private time. I hid in the closet and she went out. I heard some whispering, but I couldn't make it out. It was quiet for a bit and then about ten minutes later, I saw them coming into the room. It went very quick. He then said something about needing to get back before anybody noticed. I waited a few minutes and then came out and we had sex.

— Tony, 40