I'm not a psychologist, and perhaps the use of "sociopath" was hyperbole. And I can imagine the (to my mind) sad situation of being surrounded only by relationships so shallow that no one would suffer much distress if you just picked up and moved, but it definitely looked like that was not the case here, and I would like to think that it's not the caae for most married couples with children. I'm not saying that the sunk cost fallacy doesn't come into play when a couple is considering divorce (I suspect it's very strong), but I think that even in most divorces there are emotional (and other) repercussions that should be looked at as results of your choices rather than as artifacts of cognitive bias.
Edited 3/4/2012: I shortened up the summary a bit and add the following update:
Thanks for the lively comments. As a preliminary summary of things I've found quite useful/helpful:
It's almost one year later, and I've finally made tangible progress on some of the input suggested in my post about being non-religious in a primarily religious environment. That is, I have a near-final draft of a "coming out" statement I plan to share with a majority of those who know me.
I was involved in two religious communities for about six years of my life (SPO and CCR). Two years post-deconversion from Catholicism, many of them still do not know I no longer believe in god. This can make for awkward interactions for myself, as well as for my wife, who's still a believer. She thought it would be helpful if everyone was on the same page, as did I.