Thanks everyone for your comments. The reason I think they may get stuck is the reading I did during my recovery period. While I didn't have a traditional affair, I did have an emotional one and I found it helpful to read about the causes. A book I found helpful was written by Emily Brown here's a link to her website: http://www.affairs-help.com/types.html By her methodology, I classified my affair as a split self. According to her, the third party is frequently borderline personality. I discussed my situation with her and she believes my third party was borderline. I know there can be some overlap with traits and I thought she might have hpd tendencies as well because of her concern of appearance, fan club etc.
Emily's book and others I have read explain how women who permit themselves to become the third party in a triangle begin making sacrafices in all other parts of their personal lifes, losing their independence and in essensence wasting their lifes waiting. If you ask them they really believe they love their Married man. Reading on "the other women (tow)" website: http://www.gloryb.com/ many stories seem to fit that pattern. I think what is really happening is that they are experiencing the unhealthy competition--like how attractive, intelligent, competent women get recruited to be on shows like "The Bachlor" and then make fools out of themselves on national tv chasing after an arrogant a**. If they win the competition, they realize the prize is no big deal and begin wondering what they were worked so hard. The books I read suggest in a spring/fall relationship like I had the young other woman is recreating a competition she might have had with her mother for the forbidden attention of her father. Not sure if I get all that family of origin stuff. That is the only reason I thought she might have gotten stuck in the honeymoon phase and I think she might still be hung up on me. Believe me it''s not that I think I won some game or contest--I was in pain for a long time and she would have snapped me like a twig if I had caved in. When she ultimately moved on, just letting her walk away was the hardest thing I've ever done.
I did it because I felt I would be using her (and betraying my wife) both people who I care about. I struggled with it because I couldn't understand that if I was doing the "right thing" why did it hurt so much. Now with time and perspective I think I might very could have ended up being used rather than the user if things went any farther. Or we would still be stuck and she would have wasted several more years.
I share my thoughts about this because I have been reading (but not posting) on this site for months and found it very helpful for when she began contacting me after nearly two years of NC.
I'm out of time now but when I get sometime in the next several days, I'll share some appropriatedly edited (for identity) emails and explain how advice from other posters helped me when I broke NC on purpose to learn more about her.