Here's the breakdown on the confrontation dynamic. When your W decides to have an affair it's because she's unhappy and resents you for it rightly or wrongly.

Resentment meter at 6

She has an affair and feels guilty for doing so. Her guilt inhibits her enjoyment of her affair. She blames you for making her feel guilty and not able to fully embrace the new relationship.

Resentment meter at 8

You confront her and make statements that shame her by either direct shaming or talking about your hurt and pain.

Resentment meter goes to 10

Lid pops off and bomb drops.

If you want to prevent that. You make normalizing statements when you confront "everyone enjoys attention from the opposite sex, anyone can be tempted when their needs aren't met"

Resentment meter drops from 8 to 7

Then you distance / give space tell her you will not be in an open marriage but she can do what she likes.

What does she have to resent? You set her free and gave her a choice.

The resentment meter is your enemy, don't push it higher

Married 18, Together 20, Now Divorced
M: 48, W: 50, D: 18, S: 16, D: 12
Bomb Dropped (EA, D): 7/13/11
Start Reconcile: 8/15/11
Bomb Dropped (EA, D): 5/1/2014 (Divorced)
In a New Relationship: 3/2015