Is it permissible for a working wife to dispose of her entire salary in a way that brings her happiness—within the bounds of Islamic law—without assisting her husband, who is experiencing financial hardship, and is the husband entitled to change his treatment of her because of this?

Originally, it is permissible for a woman to dispose of her wealth in ways that the Shari'a has allowed. She is not obligated to spend on her husband; rather, it is the husband's duty to spend on her. However, her spending on him and on her children as charity is among the best ways to draw closer to Allah, for the Prophet, peace and blessings be upon him, said: "Charity given to a poor person is charity, while charity given to a relative is two: charity and upholding the ties of kinship." This achieves proximity to Allah, earns her the affection of her husband, and contributes to family stability. The wife's refusal to spend should not affect her husband's treatment of her, and the best way to overcome this is through mutual understanding and respect.