You are going through many of the same scenes that I went through, some eerily exact (like the phone).
When I posted my sitch, I think I failed to point out that during almost every confrontation (3 major plot points over the course of 6 months), she ALSO said that it is "NOT AN AFFAIR." In other words, she knew she could not deny it because she was caught, so she did her damndest to convince me that it was "not what I thought it was."
Whether she meant that: A) They did not have SEX, so it does not constitute an affair. (President Clinton said it himself, right?) B) It was just a harmless fantasy/roleacting over the Internet (although they did have at least 1 meeting that I am aware of). C) It was an emotional addiction that she was trying to break to save the marriage and family and kids' wellbeing. D) It really was an affair, in every sense of the word, and she was simply denying that because she no longer could deny what she was doing. So she could justify her true thoughts because they are still secret and I can't prove anything on that front. E) It was a penpal friendship that got out of hand and she was only continuing because she felt bad, because he was very sick and she didn't know how to just "let him down gently" (as she said to one of her girlfriends in an email I spied.)
I may never know.
She also said that it started because he was "somebody to talk to because I never talked to her."
So it goes.
Crow Jane, Crow Jane, come 'on, I wanna know,
how you love some man, but don't love me no mo'