Depth does not come without last names etc. How can that be? That's just BS if you ask me.
Ya, you have every right to put your foot down and say absolutely not. Your whole entire family will get pulled into a whirlwind of drama, bad energy and just plain ol negativity. Why? Because your husband is impatient and can't tell the difference anymore between a real opportunity and the devil herself?
I don't care what her story is, there is no reason for her to stay in her marriage at all. She has destroyed just as much as he has. Even if her reason to stray is that he beats her every night I think. Cheating is just as bad to me, it destroys the fabric of our trust of another and I would wager that it will destroy trust in your relationship too if he does this.
Casual relationships are much better pure and with integrity I have learned. This will never have any of that and all he will get is the chance to fuck someone the whole town has fucked by the sounds of it.
I'm sorry I am coming across so strongly. If you have done a search and read anything about my opinion on this and history with it, you will see why. I'm sorry if my calling this woman the devil herself offends (Mono is sitting by me telling me that is a strong word. He's catholic, perhaps its stronger for some
), I just really feel strongly that anyone who thinks ten years of affairs is something to be proud of and is cheating on a husband, a family, a boyfriend and herself is just completely lost.
I would run. I would run very fast and never respond again with anything more than you feel sorry for her and think she really should check her values.