Glad you came to the DB board for support. Your M can be saved, but a whole lot will be up to you. Don't expect her to want to work on it. Don't expect to see her change right away. You can expect her to act completely opposite of the woman you M. She is already a WAW, and she's having an A. It may be an EA or PA, but it is an A. How you decide to deal with it....will probably decide the future of your M.
First thing is to detach emotionally from your W. Hard to do, but it is necessary if you are to survive this disaster. Second thing is to pull back from her. This is what doesn't make sense to men. Even if she complained about you not being around enough or contacting her, etc.....that was the past. Now it is different and what she wanted in the past....will not work now. That's over. Men make the mistake of trying to become what she begged you to be for years. Too late now. You've got to get that through your head. Now it's time for a different approach. It will sound crazy to you, but it works!
Third, is no relationship talks. You can't fix her, so don't try. Talking from you will only hurt the situation. Learn to listen.......look her in the eyes when she talks. Just listen, and don't respond with ho you feel.
Go get a do-over on yourself and get out of the house to find a life apart from her. Yes, I know it's hard with three kids, but it can be done. You won't want to, but you need to in order to make yourself more interesting and attractive to her. More about this later.
Go get a copy of The Divorce Remedy and read cover to cover.
BTW, don't tell her what you know. Don't tell her anything right now. Hope to hear back from you soon.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!