Thank you so much everyone for your thoughtful responses.
My kids are 11, 7 and 4. All boys. They do not know anything but do ask for her when she's away. They all love her dearly. I suspect the eldest senses something is wrong. He caught me crying in my room one time. He's been having nightmares as well.
I suppose I do have to make a choice, don't I? Exposure does have its risks. This upcoming weekend trip seems to be the perfect time for exposure. I thought about telling her father and siblings who all live nearby. I don't know the effect it will have on her. I did tell her before that we will have to let our families know about her A soon and she just shrugged her shoulders and said, "Okay."
My counsellor advises against exposure to her family as it may drive my spouse away. Additionally, especially knowing about her past, the counsellor said that letting the people know who were largely responsible for her environment growing up may not be a good idea. Showing her how much of a grounded, respectful, and compassionate husband I am is my main priority right now. And not to ask questions about her affair (which I did do a lot and made me depressed).
My pastor from the beginning advised that I should let her family know. He thinks they may be able to reach out to her. And, they can't blame me later on for not letting them know early on when they could've done something to help. My pastor did acknowledge that since blood is thicker than water, it may also be risky.
I've told my older sisters and their husbands and they are very supportive. They offered their homes to me and the boys, if the going gets tough.
I was thinking of exposing both of them to their classmates. I have met a few of them and have access to their email. I think the ostracism they may receive could prove too much to bear. But I could see how that could push her away as well. Both of them may be at risk of getting suspended and/or expelled, I'm not sure.