Is it permissible for the wife to secretly take from her husband's money to cover household and son's expenses, after the husband refused to provide for the house despite his financial ability?

The wife's maintenance is obligatory upon the husband, even if the wife is wealthy. The same applies to the maintenance of young children who have no money. The wife is not obligated to spend on herself and her children from her own money, unless it is a voluntary act. If the husband withholds this maintenance, the wife has the right to take the equivalent amount from his money, even without his knowledge.