I never thought of family care as something that needs to be paid. Should I pay my wife for doing that work? In that case should she pay me for shouldering the burden of working hard in a job I don't like making money I don't spend myself?
All this doesn't sit well with me. It's too individualistic.
The law accommodates for that - 50% of the assets for each in case of divorce. Guaranteed not to be fair for most particular cases, but puts an end to the discussion, and everybody knows the deal before marrying.