What is the ruling on a wife refusing intimacy, justifying it with difficult financial circumstances and her lack of desire, and what is the ruling on the husband resorting to masturbation because of that?

A wife's response to her husband for marital relations is one of his most emphasized rights upon her, and her refusal without a legitimate excuse is one of the major sins. Mere difficult circumstances or lack of desire are not justifications for refusal. By a wife's refusal without an excuse, she becomes disobedient (nashiz). Masturbation is forbidden and is not permissible due to the wife's refusal of intercourse.