Which is much less of an issue if your own parents and grandparents (and maybe even another generation) are around to dote on your children.

Except they'd also be around to dote on your nieces and nephews (who are also their grandchildren) and the children of your first cousins (since those children would be their great-grandchildren just as much as your own children would be). In fact, because they're subject to multipliers as they go further up the family tree, they have even less time for each child.

This does not make any stronger argument against desiring sex without conception, not does it weaken my "only thirty hours in a day" argument for sex without conception.