"WHY??????? Why would you sleep with a married man? One with children?"
Because the only thing he is not getting at home is sex. He's happy there except for that.
"Knowing from the start he will NEVER leave his wife?? Did you consider her feelings and what it would do to her? How would you feel if you where her?"
Yes, and I hope she never knows. I don't want him to leave her. I hope things are better for them because he can love her and stay with her and not make her unhappy by trying to get her to have sex with him when she doesn't want to.