What should I be doing now? (It's done)

[trumpet]

I would have responded to the EXWW the 'next day' with an 'OK'. Nothing more. Maybe 'thank you'. But really, I would have made it pithy. But that's just me...

You don't need to explain yourself. I even think you could have gone a different route and NOT told her you are angry. Showing emotion to someone who doesn't care about you anymore, or harbors resentment for you, can be a door of opportunity for them to strike at you.

Complete detachment means if they get angry or upset with you, you shrug your shoulders, turn around, and walk away. At least that's what it means in my book. Easy in theory, hard in practice, as we have wounds that go deep, and the person we dialogue with knows our 'hot buttons'.

BTW - "I know you think I'm this horrible person" = she thinks she's the horrible person. MY EX said this many times. Her guilt 'meter' used to work. It broke during her affairs... at least it seemed to. Now? Who cares.