Now that she's gone and I have time to think (and yes I do GAL and other things as well), I am trying to fathom out how a wife and mother who had good morals can suddenly go wayward with no time in-between the transition.
People love linear systems and immediate feedback -- I press the lever and I get a pellet. I can understand that.
Relationships are highly entangled, hugely complex organisms laden with long delay feedback loops, outside influences, historic baggage, etc. When relationships break down you want to put your finger on the exact "why" so that you can learn from that, but more importantly take measures to protect yourself from having it happen again.
When you can't figure out the exact why, you can't put a targeted protection plan in place, and therefore you feel exposed.
One of the singular most painful things about this process is never getting to the "why" in any kind of satisfying conclusion.
There are thousands of small contributors, and you can treat and improve upon each one, but you probably won't feel that the sum of those changes fully insulates you from experiencing a loss like this again.
The first phase of this journey for most is guilt -- searching our memories and inventorying all our shortcomings. The first reaction of some people on this board to a newbie is often "you weren't meeting her needs" which further reinforces this stage of guilt.
Relationships aren't that simple. If you weren't meeting her needs, chances are she wasn't meeting your needs either, and the reasons for that are many and varied. A relationship is an equilibrium between two personalities, and its state is a reflection of both contributions to it.
Point is, regardless of the affair one or both of you weren't happy. Usually its just a matter of timing in terms of who pulls the rip cord first.
That's why it's now important to separate the desire for the person, from the desire for resumption of control, stability, and positive validation. Your brain is telling you that getting W back will restore these things, but it won't.
So ask yourself, what do you want and why do you want it?