The question is are you seeing it more like a friendship or are you getting "intoxicated" because it's another drug to substitute your W? You've shown in the past that you've substituted one form of addiction for another. I can see this as being the same. That's why you're falling so deeply for this person.
This is kinda what I was trying to get at.
He feels guilty because he's made a big deal about "standing" for his marriage and he's "struggling" because he sees an opportunity for a quick fix for himself.
It you're standing for your marriage, the answer is clear. Enjoy her company, but make it clear that you can't offer her any more than friendship.
Me: 44, Wife: 39 M: 17 years T: 20 years Bomb on 08/25/09 1/13/10: MC started 1/28/10, 2/8/10: More bombs 8/28/10: Wife moved out No talk of D, no movement