[kelnos]

Only two of the things you mentioned (private school and college savings) are unique to people with children.

All kid-related expenses (including private school and college fund) should be considered joint expenses and come out of the shared pool of money. Parents should agree on how much to spend monthly/yearly on non-essential/fun stuff for the kids (similar to how the parents each get their own fun money allocation). If one parent wants to exceed that for a one-off thing (and the other parent disagrees), they can dip into their own fun-money allocation.

Couples without kids still have to decide what to do about home improvements, vacations, vacation property, cars, and rainy day funds. It's just that couples with kids may have less money to allocate toward those things, or have to make harsher compromises. But hey, if you decide to have kids, that's what you've signed up for.

A couple might agree that replacing the old, fraying carpets is obviously a joint expense, but the fancy car that only one spouse wants and cares about is a personal/fun-money expense. Having or not having kids doesn't change that.