I've also been a stay-at-home mom all these years - with one exception. I started a business at home almost 16 years ago when my youngest was just 3 weeks old in order to take some of the financial stress off my H. So I had 3 kids under the age of 7, the youngest two were only 18 months apart, staying at home to raise them all the while trying to run a business. I would spend 14-16 hours a day for the first 5 of those years working, even on weekends. My H felt "neglected." That was when he had his first A. Did it ever occur to him that I was neglected? That I was doing everything for everyone else and had no time left for myself? I really thought he valued what I did. He always said he wanted me to stay home to raise the kids. That was what I wanted, too. And I really thought I was being a wonderful partner by trying to help in whatever way I could to take the financial stress off of him. Now to hear him say that he felt "neglected" and turned to another is not only heart wrenching, but deeply disappointing.
I'm not really sure where I'm going with all this. Maybe just needed to get it off my chest. However, one thing I'd like to say is to make sure your W knows just how much you value her for her role in bringing up your family. I truely believe this is the most difficult and most important job in the world. Just make sure she knows you feel that way, too, and truely appreciate her for it.