I read a book on a negative marriage spiral that I think is related to this as well. It was more slanted toward WW but works both ways I think. Here is the cycle in some marriages, although not all A start like this but some do:
Early marriage good relationship, good sex life
Life gets busy, work kids or whatever, emotional needs are not being fully met. At the same time some women's sex drive diminishes. This cycle does 2 things: often the woman's need for emotional intimacy not being met means they feel unloved and the man's need for love via sex is also diminishing as sex life drops. So both parties potentially feel unloved to some degree. And one may exacerbate the other: I don't feel loved so I am not in the mood for sex, I don't get enough sex so I don't feel loved and then I don't give emotional intimacy.
Now either man or woman is ripe for an A if they do not have good boundaries and/or they have significant interior issues they are plagued with relared to self esteem or whatever.
The addiction related piece is that neither one is getting what they need so when they start getting it from someone else, the dopamine kicks in potentially very strongly. It can be very powerful... making them feel like this must be true love because why else would I feel this way? I dont feel this way with my spouse, but I do with AP. Not logical in many cases as they dont really even know each other. The author explained that if the woman is wayward and her sex drive had diminshed somewhat during marriage with her husband that it can come roaring back with AP due to this dynamic.
As I mentioned, it is clear that not all A follow this pattern. But quite a few are related. The addictive nature of the dopamine release is certainly a very real thing and it drives people to do and say a lot of things they otherwise wouldn't.
The other thing that comes to mind is a sexual fantasy. Most people have at least a few and they can be pretty powerful. Thinking about it turns you on or helps you orgasm more quickly. It helps me understand the nature of an A because now imagine you are getting this switch flipped through texting, sexting, conversations and secret hookups. It's a fantasy but it's being driven with interactions with another person, sometimes hindreds a day with texts etc, instead of just in our own mind. When I think of that I think what it would be like to turbocharge my sexual fantasies like that and it sounds pretty powerful, doesn't it?
I am not saying that all A are about sex, just comparing the A fantasy to something most people have...a sexual fantasy.
[This message edited by Trdd at 12:12 PM, Tuesday, March 5th]