Checking out of the marriage is not being present in the marriage even when together. That isn't detachment. Really detachment is getting to a place where her words and deeds no longer affect you emotionally. She could tell you she had a gangbang with 100 people the night before, and it would be like water off a duck's back to you.

I would consider asking her to leave the MBR. We recommend LBHs with a cheating W kick their W out of the MBR. I am guessing based on her behavior, she has cheated with this OW.

M(53), W(54),D(19)
M-23, T-25 Bomb Drop - Dec.23, 2017
Ring and Piecing since March 2018