I thought about the revenge factor. I am sure that on some level there is revenge, but a lot more of this is about how is simply enjoying being with her. Revenge would be me doing something to hurt W. In all honesty, it was more for our benefit, each of us having an intimate moment with someone we cared about. And that attraction pre-dated my marriage.
I'm well aware of the fact that I'm not to blame for her poor choices. One of my friends mentioned that I've done everything I could to end the A and make it as easy as possible for us to attempt to R.
As for me keeping my coworker as a backup, the problem is that she's not close to where I'd be living, and is very much tied up with her work and her child (and no, she's single), so I won't get a chance to see her. Perhaps emotionally she can fulfill some of my needs in the short term, but time and distance tend to undermine that.
As for me, the moving day comes up shortly. I am not inviting W to my going away party and I hope to move without her coming around. The NC will probably be modified at some point since she will be a distance away. I won't contact her much, but I may respond to texting or e-mails a little faster or have short text convos.