If they are cheating, then you are now cheating as far as I am concerned. I suggest having some compassion for the women they are cheating on... how would you feel. I would take a good long look at your integrity and how much it is worth.
In the mean time you might want to have a look at the many threads here on cheating... you can find them by doing a search on the tags for "cheating" and "affairs."
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