There's been a lot of conversation in recent pages about the NK/CW dynamics. Having been through an intense affair, perhaps I can add a little perspective.
One thing that both parties experienced in my affair was deeply conflicted feelings. On the one hand, as good people, we wanted to do the right thing despite all the wrong feelings going on. On the other hand, there was an undeniable force that seemed to bring us together. It sets up tremendous emotional churn. There are different ways to respond to those feelings, such as trying to stay apart, coaching the other party on how to make things better in their marriage, etc. etc. The attempts may be well intentioned and sincere, even as the heart swoons and the affair blazes on. It may not make sense from an objective perspective, and it is very hard (actually impossible) to reconcile the two forces. A choice must be made.
Another characteristic I would say is the temptation to lie to serve the interests of the affair. There certainly is a huge amount of deception with one's spouse(s) to account for time away from the marriage, spiriting secret funds to spend on the affair, apparent loss of interest in the home life, physical and emotional distancing, etc. The lying can also extend to the love interest. This may include portraying one's spouse or marital relationship negatively to help justify the affair, misrepresenting intentions, and so on. One nasty thing about affairs is that they can turn otherwise honest people into liars.
A third characteristic is how obsessive one can get thinking about the love interest. I'm not normally an obsessive guy, but when one's heart is singing, when life now has vibrant color rarely seen, and when you feel poetry all around you, it is hard not to think constantly about the person who is enabling these amazing feelings. And of course there is the sex, which doesn't need explanation.
When I heard some of NK's interview, some what she described resonated with me as likely truthful. For example, coaching CW on his home life and relationship. I don't see that necessarily as NK trying to come off as blameless; I could easily see her expressing conflicted feelings and trying to 'do the right thing' with CW even as she fostered the affair. I would guess there are probably few women in affairs who like the thought of breaking up a family, especially with young children in the picture. I'm not defending NK, just pointing out that some of her apparent inconsistent behavior may actually have been genuine and not uncommon to people in affairs.
With CW, my hypothesis is that combining the incredibly powerful feelings that come with an intense affair, a psychopathic lack of empathy and moral obligation, and lack of emotional and general intelligence, and you have a recipe for disaster. I do believe that NK unleashed new self-awareness in CW, and that is does take a certain chemistry with the love interest to catalyze this (it was likely more than just about sex). Unfortunately, the self-awareness was narcissistic; and as a formally awkward guy who was marginally attractive, CW felt an over-compensated sense of power and potency. It probably was very difficult to contemplate walking away from NK and all she represented to him, and I have no doubt he obsessed mightily over her. But while most men may seek divorce as the only way to preserve the new relationship, the psycho in CW actually thought murdering his family was a way out. From my experience, I can relate to much of what occurred between NK and CW leading up to that horrible night. But Chris stupidly boxed himself in with lies to his love interest (he clearly was NOT very smart), and, in a flash of incredible cruelty and short-sightedness, wrapped his hands around Shan'ann's neck that night.
Chris made his choice.
I'm in the camp that CW is psychopathic and had contemplated murder as one of his options before that night. The evidence suggests he may have even targeted that night. But he may have limited his thinking to a more abstract level, because he clearly was not much of planner. Beyond the idiocy of boxing himself in so badly with NK, and beyond the moral horror of murder, the utterly unfathomable stupidity of his thinking that he had any chance in hell of actually getting away with it is impossible for me to comprehend.
And that 45 minute drive to the oil field. The time he had to think. Those babies...
Good God what a monster.