that a really tough spot to be in - i know, i've been there (or near there at least
.
i don't have much to offer over what others already have, other than my sympathy and well wishes.
in my case, i tried to work it out for a long time but in the end it was no good. i was never able to really trust her, and she was never able to stop cheating. in retrospect, i wish i would have cut my losses a lot sooner.
good luck.