Yep -- and the "eros" love toward a spouse is physiologically blocked when one is in an affair with someone else.
Oh I don't know if that's true. I've got Miss Someone but that doesn't stop me from hotting-up over WAW more-or-less every time I see her.
If this paradigm is correct, I suspect eros is the most fleeting, least sustainable of the lot -- so when You've Lost That Loving Feeling, you've lost it, whether or not there's an OP. Doesn't mean you can't get it back, but at the moment it's gone. (Whooa-ah-o-ah-o!)
The problem is, as @Kettricken pointed out above, many many people act on the moment. This, indeed, is something WAW said in re: the Bomb at Fab MC#2 -- "I don't know, right then it just felt like the right thing to say." (Which is why, incidentally, so many times after, when Herself was complaining about alimony, etc., the deer-in-headlights-look would materialize whenever SP Himself said, "So, what? You didn't think about that before you did it?")
So yes -- when the moment is right (wrong), WAS acts. On the spur of the moment. Based on the feelings of the moment. Rather than (SP Himself said smugly) on the basis of sober reflection and....analysis.
