Your sitch is atypical, but I think DB'ing will still benefit you. Have you read DR? If not then pick it up right away, it'll help a lot.
I think it's common for us guys to look to the future for cures to our marital problems. When you say you were looking to retirement for everything to get better, I likewise saw a lot of problems in our M but thought we could right all the problems after the kids moved out and we retired. I was content to live with things as-is on the hope that the future would be better. It never crossed my mind that W might feel differently, and did she ever! While I was patiently waiting it out she was quietly planning her escape. I suspect the same happened in your M.
Since you've been separated for quite some time already, the normal DB'ing advice of detaching and getting a life doesn't really apply to you I don't think. It might be a good idea to talk to a DB coach because they have more tools for specific situations like yours then we do here on the forums. But feel free to journal here and we'll help as best we can.
