You don't know his intentions, so ask him what his intentions are! If they go underground or something else, that's their decision, but capitulating in this fashion is showing BOTH of them that you are weak, which certainly isn't attractive to your W if that is your goal. She has to respect you as a man before she can respect you as a mate, and you aren't giving her any reason to. You have every right to question this person and his completely inappropriate behavior.
That may or may not be the DB approach, but I wouldn't care. There's an inappropriate relationship with YOUR wife in YOUR house with YOUR children present. I am not intending to come down hard on you, but I have no idea how you can sit idly by and watch this.
-PM
M:12y - BD:12/11 - D:6/13 - 4Ds
"The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy." -MLK Jr.
