Ok parent b is definitely not a leach.
That's an awful way to phrase the mother of a child. ..
What does parent b have left over after nursery?
Fwiw I was a sahm for ten years, I always bought the weekly food shop as a regular main cost .
Now I'm working i add to all our pots at what I feel I can afford eg I give DH 100 a month to go where he wants it to go .. savings or a fund we have for our childrens clothes, school cost.
I also give a further 150 again to go where he wants plus small overpayment on mortgage.
I give 75 towards Xmas per m. 75 to holiday's, and I have my own children's fund for tutors which I also pay into.
( Not exact figures but as a rough guide)
I pay for my own car costs, insurance etc and still pay for food. .
It's not set down as a % of what I earn it's more like what we both, every penny is assigned.
DH definitely cooks and will if I ask him but I do 75 % of meal planning, buying and Cooking, as well as the majority of washing and house work and 99% child admin, hospital appts and so on.
It's solely me who notices problems with house and gets them sorted out etc etc.
I earn nmw and earn around 940 p m.