"it reminded me why I was getting ready to leave about 5 years ago!.."
This is key. and very very important for you to think about and own.
I would guess she sensed this, and for the years since has taken on this same feelings herself, hence the A.
and i say this because i was the same. i checked out of my M too, then partially came back, going through the motions with some improvements, but never fixed the issues.
when she dropped the bomb i was shocked - which was ridiculous - but it wasnt so much that i was surprised she did it, but it was then that i finally realized it went to the point of no return, there was no fixing it -- and i didnt want to admit this to myself.
its a tough realization, but your statement was very likely the trigger point that started this phase of the R.
"In a ham and eggs breakfast, the hen is involved, but the pig is committed".