Your wayward is not the exception
A word for newbies: your wayward is not the exception.
Immediately after D-Day, do as everyone on TAM says: expose the affair, agree to let them go, file for divorce, show no emotion, kick them out of the house, and absolutely no contact until the affair is done.
When I read all this after my D-Day, in my confusion I had this thought: that's wrong for my situation because my wife complains I'm inattentive, so I have to be attentive. And so I made the mistake of trying to romance her, etc. She reacted positively in the short term, but ultimately it was a waste of effort. By the time I started becoming firm about 2 months in, it was too late. Now I'm preparing the papers.
I still don't blame myself for anything though, all goes back to her decision to cheat. Someone should invent a wedding ring that shocks waywards when they cheat, like an electric dog collar.