This isn't really about your wife it's about the loss of control and the fear of the unknown. This on top of a man's propensity to try to fix things and it's a receipe for disaster. You start operating under the illusion of action where you feel you need to do something to get her back. The best thing to do and would be the ultimate sign of love and that is to give her the freedom she is requesting.
I would love to see the stats on busted divorces if at the bomb drop the lbs said "lol oh you want to leave me? Well that's not what I want but ok. Do you need help packing your bags?
That's the mindset you need to develop because right now you are chasing a cat and it's going run every time you get close to it.
