Not to sound all 99%, but I think that there are a lot of assumptions taken in this (and most similar) article(s). I know that it's based on studies, and that each person/case is different, but assumptions about guilt, time management, and spouse involvement seem awfully...assuming.
'Schedule time for yourself' is good advice, but who is going to watch your kids? Trade time/kids with a friend? Otherwise you'll need to pay a babysitter, which may not be doable...especially if you're a "Stay-at-home mom [who] feel[s] insecure because [you] don't hold down paid jobs..."