There won't need to be CSA payments if both parents work 20 hours a week.
She hasn't been sitting on her backside, she's been raising her kids.
If men did more of that, it wouldn't be called "sitting on your backside", it would be recognised as the work it is, because men would be doing it.
There is a massive resistance by some people, whenever this solution, which promotes social, equal and parenting equality, is suggested.
Fifty years ago, the idea of women in the workplace after they'd had kids, looked impossible.
Women showed that it wasn't. Men have to show, that the idea of them taking equal responsibility for parenting, isn't impossible. They have to want to do it and they have to do it. And then if their relationship broke down, there would be no question of only one parent bearing most of the responsibility for continuing to parent that child. It would be obvious that both parents have been responsible and will remain responsible.
The group which can make this happen by campaigning for rights and actually doing it, just like women did, is men. Let them get on with it and support them to do it, instead of pretending it's impossible.