There is an element of pretending at first. We call it "fake it until you make it". But the idea of detachment isn't necessarily and outward thing. It is inward.
I like to say that detachment is getting to a place where your W could come to you and admit to an orgy with 12 guys, and you would have no visceral, emotional reaction to it. In other words, not being emotionally affected by her words and deeds.
I think I have a way to go in that area then. How can I not feel hurt if something like that happened?