First off,
Both my best friend from school and SIL have had to deal with this. In BF's case, he cheated while they were DATING, she left, forgave him, came back, and years later it all repeated itself TWICE. Once with a prostitute.
I am not kidding.
SIL and her DH have been married 15 yrs. DH and I have been married 10. As long as I have known her, she has been going through the "cheating cycle". He cheats, she leaves, she forgives, she goes back, and it just repeats itself every few years. Meanwhile she shares very intimate details with all of the family and now that she is back with him, can't understand why no one wants to be around him.
I think every situation is different, just as every relationship is different, and I don't know what I would do faced with it, besides wanting to leave him with one less body part than he came into this world with.
I do know that from what I see, neither BF or SIL will ever trust their DHs again. Any time their DHs are not instantly accessible, they freak out. That being said, they will both tell you that they made the right choice in sticking it out and staying. They both have children with their husbands and maybe they feel it is worth it to stay for the kids.
There are no easy answers here. You must analyze your relationship and decide if it is worth salvaging to YOU.
Hang in there and I am sending you lots of "Girl Power", as DD would say.
