The rules changed, it used to be 30% of your salary cash.
Not anymore.
Now both have to pays the expendichures 50/50 unless there is a huge gap between both.
But you can pay in goods because the money is for your child. So now it is Ok to pay the school, to buy clothes or food instead of cash.
Interesting. That would be much more preferable so I know the $ is actually going to my child.