[rich_sasha]

One thing that's massively changed, at least in my corner of the world (various bits of Europe) is that grandparents used to be much more involved in raising children. Nowadays, they are more commonly uninterested, living far away, or lack the past societal norm pressure. EDIT: Or are older, as they themselves had children later than past generations, and therefore less able to help.

Without that unpaid, keen, trustworthy workforce, raising children is much, much harder. You either have to rely on paid (very expensive), and variably-trustworthy professional childcare, or put something like 50-60 hours a week of childcare. I'm talking about everything other than normal working hours, where typically children are at school or nursery etc.

Soo... this extra pressure is enough I think to bust a marriage with children (it seems that parental separation rates are increasing, with or without marriage), or to put couples off having them in the first place - in which case the utility of a marriage in a secular world is much lower. In the UK for instance, next to none.