And don't forget that Steven DESPISES the Mormon church. So, Josh and Susan live in Utah, where divorce laws really favor mothers. In a divorce, Josh would have gotten visitation, in all likelihood. That means that the boys would be raised LDS - by Susan, and Steven's indirect influence over them would be almost completely diluted.
And from an outsider's perspective (an LDS outsider), the first question I'd ask Steven is, "Do you think that part of why you became so disgruntled with the LDS Church was to repress the guilt you feel FROM LOOKING AT CHILD




?"
But I digress.
Anyway, it's not all that far fetched a scenario to think that Josh doesn't go to church Sunday morning, Josh and Susan argue about it for the hundredth time, Susan says something along the lines of, "You know, this just isn't working," Josh calls Dad to whine about it, Dad goes on a diatribe about how THAT #$%!@# MORMON CHURCH DESTROYS FAMILIES, and Josh and Dad decide to do something about it.