"Here is another question - given my W's mental state and her seemingly need for attention and acceptance, does the whole detaching and not showing attention and the like just validate her feelings of moving on?"
Detaching is for you, E.
Who knows what your w is thinking. I'm sure she is a roller-coaster of highs and lows. I remember in my sitch, I was SUPER paranoid and was hyper-vigilant as to what I said or didn't say.
I was worried she would think I didn't care by going no-contact. I looked for reasons to justify reaching out to her. The vets here kept me straight and held me accountable. I listened and didn't waiver.
It's ok to show some attention if she is still in the home. Just do it from a place of detachment, don't do it expecting a reaction or for her to suddenly snap to her senses. Make sense? If she is the type that needs attention and validation, do you plan on doing that if she divorces you? Maybe she needs to feel a sense of loss. Get busy doing things, make her wonder why your life seems so fresh and exciting.
The key is to be ok with you. Before you can be ok with her.
Regarding validation, you are not validating her leaving. You are validating her FEELINGS that she is hurt and confused. Don't confuse the two.
And the anniversary thing, don't look into that. Think of your w as being temporarily abducted by aliens. They brainwashed her (fog) and it's going to take some time for her to find her way out. And remember, you can't help her find her way out. But you can keep the front porch light on for her.