I am strongly in favor of exposing affairs to the cheating spouse's family, but ONLY if they are pro-marriage and pro-YOUR marriage, and you think they'll be supportive. But if they are, then "a", they should know the truth, and "b", maybe they can bring some pressure to bear.
Of COURSE it will piss your wife off. But that's neither here nor there. Mine got over it, and actually THANKED me later, for fighting for her.
