Personally, I think it goes down two ways. The chemicals behave in the brain as described, but the resulting behavior can vary.
Instance the first, like Puppy describes. Maybe it's a manifestation of cognitive dissonance. Convinced that OP is their at-long-last-discovered one-and-only soulmate and/or chance for escape/self-realization, the walkaway can't afford to give the LBS even the ghost of a chance. Can't endanger that French Connection, after all.
Instance the second, good sh*t is good sh*t. That sexual energy generated by the affair (EA or PA) gets channeled back into the marriage bed, too. For what could be a staggering variety of reasons.
You could possibly advance the argument that the first scenario is more likely to apply to women, and the latter to men. Although there's probably a lot of bleedover, depending on belief system and personality type.
Interesting theory, Kett, and certainly not a small amount of anecdotal evidence that waywards can be quite, shall we say, "libidinous."
I would still contend, however, that this is purely a PHYSICAL reaction to their LBS, driven by these same hormones, and I would still contend that a WAS in this state is largely blocked to their spouse emotionally.
