I didn't fit into some of the boxes either. For years I was much like your W. I had carried resentment and disrespect around in my heart for years. I had a lot of unmet expectations from M, and unmet emotional needs. I was always trying to find something that would make me happy, to fill the loneliness and stop the depression.
I used to be embarrassed to admit it, but I was hooked on romantic novels. The embarrassing part is how it would leave me feeling so hungry for love and romance. It actually made me more resentful toward my H for not being more like the hero in the novels. I would see our neighbor who was constantly working in his yard or remodeling his house, and resent my H for not being like our neighbor. I was bad about comparing my H to other men.
Over time, I became more & more depressed about my life and all the "bad stuff" that continued to happen in our lives. It's a long story, so I won't get into it any further, except to tell you that I became very vulnerable. When a person is "reaching out" b/c they are unhappy, lonely, and trying to find comfort, love, excitement, companionship, or whatever.......they can get into trouble pretty quickly. If you had known me, you would have said I was the last person to do what I did. And, I would have probably agreed!
I am trying to say that when certain conditions continue for a long time......a person can become vulnerable to things they never were in the past. That's not an excuse, and I knew better. All it took was someone saying the right thing that fed my ego and made me feel in a way I had not felt in a really long time.
So, I can see the same thing happening with your W. Whether she's in an EA with your friend, or not, she is vulnerable for one. She put herself in this position of vulnerability, b/c of her mental attitude and how something/someone is suppose to make her happy.
We have had former LBH's who would discover the W was in an EA, then approach the OM and find out that OM knew nothing about the WW's feelings. I believe that is quite possible in some situations. I think your friend should have been a heck of lot smarter, if he really is as innocent as he claims. However, that doesn't mean she wasn't having feelings for him.....and allowed those feelings to affect her MR.
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!
I would see our neighbor who was constantly working in his yard or remodeling his house, and resent my H for not being like our neighbor. I was bad about comparing my H to other men. 