"With all the turmoil in my life, I have not been a great son. Pretty self absorbed. I am pretty exhausted. I am not eating well or sleeping well." Don't stress about this. You have to put on YOUR oxygen mask first THEN help others. Take care of you, hence getting a life.
I know you talk about going dark, but in my experience, you can never go truly dark while living in the same home. That's what I struggled with. It helped me to ALLOW myself to be myself and let go of some of the anger that was turning into resentment. I didn't forgive/forget, but I let it go for me. I didn't pursue, ask about her day, but if she asked about me, I'd allow myself to answer, say thank yous, even make a joke once in a while. It was killing me to be cold and angry. Ultimately I had to move out to where NOW I can go dark and control the interactions I have to ensure they are positive - that's key. If you don't or can't have positive interactions with WW, why would she want to come back?
I do understand the hurt, anger and disrespect. While she's having the affair, you aren't her friend, but as the mother of your children, you coparent and treat as a neighbor. Neighbors say thank you for cooking and even listen to stories, but go back to the main focus of their own families quickly.
I'm not telling you you have to move out or even that you should. It was at a point where I needed to for my sanity and to truly go dark. Not sure how anyone does that living together in the middle of the affair. I would assume cake eating runs rampant in those sitches.
M-33 W-33 S-11, S-8 M-11, T-14 BD - 12/26, Divorce Filing and admits to affair (her) 4/18 I moved out 5/23