He was forced to take part in a gangbang and it got him to thinking he would like to see his wife with another man. The story is in six chapters; the seventh will have to be in your own mind.
A Story in the Disappointment, Betrayal, and Revenge Universe
One man learns that self-deception is the easiest kind, and that trust is sometimes rewarded with disloyalty. He survives, though, and life goes on. This is not a story with a happy or satisfying ending! If you can't handle that, don't read it.