I feel for all of you guys dealing with the issues you/I am. At least all my kids are in their 20's and I don't have to go through that issue, although with my W's first "vacation" 15 years ago it was similar to what most of you guys (and gals) are facing.
It does get better with time, and each sitch is different. Sometimes you go with what you've learned in the DBing and other times you trust your gut. Dim/dark-detach/nc-listen/validate, it's NOT easy to know when to do what, and when you screw it up-well we are all just humans trying to deal with what seems like aliens on some days.
Good luck to all of us in improving OURSELVES no matter what the outcome is with our M's. That's really the point anyway-right?