Your wife is likely going to go ballistic this week, over the exposure to your sons and the parents. Do not feel like you have to have a ready response to every ridiculous statement or accusation she makes. Learn the fine art of the following few things:
1) Simply shake your head in astonishment, and say "Unbelievable," and walk away;
2) If she asks you about the R, say "Unfortunately, we HAVE no relationship so long as you've made the unilateral and destructive decision to invite a 3rd person into it. End your affair, and we can talk about it."
3) If she asks you about a divorce or separation, say "Unfortunately, this is a legal issue now and better left for the attorneys."
4) When in doubt, simply say "Let me get back to you on that." Don't feel like you always have to have an answer for her. In fact, most of the time, she deserves none.
Keep us all posted, and we can help. You're doing great. In the meantime, WORK ON YOU, and just be the World's Greatest Dad to those boys.