You have some great points. I could certainly use your type of spin and back out of the exposure. I can tell her that I was angry before but I've moved past it which is true. I can tell my W I came very close to exposing the A to the OM's W but I just knew it would mean her world would come apart. All of it is true.
There is NO spin. It is you being a man and admitting to your wife you messed up because you let your emotions control your rational thinking.
If you try to but a spin on it she will likely see through it and it could very well blow up in your face. You messed up... own it.
It isn't just her world that will be shaken but a whole other family. It will cause needless pain and heartache.
I have a mantra that I have used during my entire D process. It is Class, Honor, and Dignity or CHD for short. Every word that comes out of your mouth... every action that you take... every thought you have should follow this.
I believe your W will be more impressed with you being honest than putting a spin on it to make yourself look good.
“Things turn out best for the people who make the best out of the way things turn out” ― Art Linkletter