For what it's worth, here's what I can offer. In the ten years of my rocky M, including one brief separation 8 years ago, I could always feel that my W and I were still "married". We cared for each other, and our attempts to work on our M were sincere and appreciated by both of us. It was different last year when my W just seemed to be "gone". Nothing I did mattered. She just didn't seem to care, and something was fundamentally different in our interactions. She started disliking the things we used to do together, she started acting aloof. She seemed absolutely certain in her decision to leave me and get a D, with a cold detachment I found shocking, given we have three little kids. If I even mentioned anything about whether it was good for the kids, or that we should work on it, she just got very angry and attacked me. When I found out she had been having an affair for several months, all was made clear.
