Out of curiousity, why would she be detaching from me? Is this finality on her part as she has not at any stage tried to talk about our relationship - it is as though she has just turned a switch off.
Think of a child with their fingers stuck in their ears, making loud "nyah-nyah-nyah" noises and saying "I'M NOT LISTENING . . . I CAN'T HEAR YOU . . . "
She probably doesn't want to let any FACTS (shared family history, wisdom of running away from her problems vs. trying to solve them, commitment to her wedding vows, etc.) stand in the way of what her EMOTIONS are telling her right now, and that is to FLEE.
Fairly or unfairly, when someone is in this wayward state, they will make YOU the source of ALL of their problems, all of their anxiety, all of their pain. YOU are responsible for the demise of the marriage, YOU are responsible for not "hearing her" when she supposedly reached out to you (questionable; you're expected to be a mindreader), YOU are responsible for pushing her even further away these past few months. Hell, you are even responsible for the crisis in Gaza, the budget deficit and the fact we haven't found a cure yet for Alzheimer's.
Get it now?
I think you will be surprised at how she reacts if you truly "drop the rope," take a stand for your own integrity, and begin to emotionally move on. But do NOT merely do it as some gambit, some technique. You have to truly be ready to begin to emotionally walk down the Path that is The Rest of Your Life, without her.
I'm sorry -- I know this sucks. But it's your only chance, in my opinion.