You're doing better than I did. I congratulate you.
I'm all for blowing the affair open, but only calmly, and stating your boundary (for me, it was not willing to be in an open relationship).
So far, she thinks you have put up with her double-life.
Sandi would have much better words of wisdom for you. I just know going full-on Bull-in-a-china-shop doesn't work well.
Go in with your end-goal in mind. Saving the relationship? Don't burn your bridges in the first 5 minutes. Don't use righteous anger to drive your wayward wife to the brink right away. You want her actions and feelings to convict her.
You must be strong enough to walk away. If not strong enough, at least strong enough to separate to work on yourself.
Sandi, mutatio, et al???
M46, EXWW46 M15 T17 D20, S19, D13 M - Addiction since 1998 W EA/PA #1 2013/2014 W EA #2 June 2015... BD 1 Big D talk 9/15 BD 2 - EA/PA disc 10/30/15 Served D 1/22/16 Divorced 5/25/16 (yes, that fast!)