Not to judge too much, but that sounds more like the outcome of a crappy relationship rather than a universal experience.
Not exactly related, but ... I will admit, I'm occasionally mind-boggled by family court. Male rape victims have been made to pay child support because its not the child's fault that his mother was a criminal.[1][2]
Child support is nearly universally enforced at least on paper. The incentive is to divorce quickly after a high earner scales back to lock in the high imputed income. You see sky high divorces in recently unemployed persons as spouses scramble to lock in CS and alimony against their recent earnings.
These are the acts of calculated actors getting in on the take as incomes reduce, to lock in the income stream.
These are the acts of calculated actors getting in on the take as incomes reduce, to lock in the income stream.