I pulled a few things out of your posts to try and wrap my head around things.
May 2016 she fvcks the dude.
October 2016 the day after your 9th anniversary, she want to break up, reveals adultery, and has already found a monthly rental apartment.
October 2016 a few days after DDay she wants to talk about "our feeling about the situation". Your agenda for the meeting is to split assets.
November 2016 she responds to your Mom's email with, she "doesn't deserve RickyBobby's love, respect or trust"
March 2017 at the meeting to sign the agreement, she refuses and says she made a "huge mistake". She follows up with a note that she "wants to come back" and "has wanted to come back" but hasn't because you don't deserve her.
I'm trying to understand all of this in the context of her longstanding inability to find her voice and express her feelings. Throughout the marriage I take it.
The gap between the May adultery and the October DDay the day after your anniversary is notable because you didn't notice any change in her.
Her DDay was planned included securing an apartment. Adultery was always a stated deal breaker for you. You told her to get out and she thought that was going to be your reaction so she had the apartment ready and available.
So she pops up a couple days later to discuss "feelings" about the sitch, in November makes a statement to your Mom about not deserving your "love, respect, or trust", and in March opens up (a bit) when the opportunity occurs surrounding the signing of the document.
Next there is the whole "greener pastures" thing. The cheating with the Ex/OM dude is a one-off. So she hasn't been dropped by him. She makes good salary. Her job is portable, globally. She is good at what she does. So there isn't any economic imperative in play here.
Chamo writes that either the grass wasn't greener or she has found her remorse. DM writes about people that "stuff down" their feelings. Astute members.
I don't think she has the capability and capacity to find her voice and express her feelings. Virtually incapable of doing so. Consequently, you get nothing in the way of deep, emotional conversation. She simply can't express it.
It was as if she was resigned on DDay that the outcome was foregone, hence the apartment. True, she knew cheating was a deal breaker. But she seemed unable to articulate anything after 5 months of holding onto the adultery.
I believe her when she says she has always wanted to come back. I just think she doesn't have the capacity to express what feelings she does have. Therefore you have no way of assessing her. Any actions she takes, or should take, would come from a place of knowing and expressing her feelings.
I'm left with this: She knew cheating was an absolute deal breaker, confessed and had her exit planned because it was a deal breaker for you, surfaces every now and then (almost always when given an opportunity by others), and makes some expressions of regret. Probably all she is capable of expressing.
This nags at me from DDay:
She then finished with saying I was her best friend but that she now felt the marriage was a sham and wasn't committed to it.
She has to overcome this statement. Otherwise I only see regret. Unfortunately for her, she doesn't have the ability to identify and express feelings.