I think you are in a much better sitch than most...it seems you may have taken her seriously early enough to make impact before BD. She may not have had an A yet, but she certainly seems like she was on that path.
Time to get busy with you. What are your 180s? What are you working on? Have you read DR and 5LL? Clearly you are not fufilling all of your W's needs, so dig into that and figure out what's missing. What have been her complaints about the M?
I don't know a lot about MLC, but it does seem that an awful lot of us end up in this type of sitch in our 40s. For me, I pretty much lost myself over the course of our M and our struggles. 15 years later, I'm a shell of the person my W loved. Doesn't take an expert to see where that leads. One partner starts questioning the M, their life, their happiness, etc. and given that their spouse is always there, it's pretty easy for that person to end up taking the blame (sometimes rightfully so to a point).
Take a hard look at yourself. Are you who you want to be? How are you different from who your W fell in love with? Are you meeting her needs?
