What is the ruling regarding a woman whose husband has forbidden himself from her until the end of the month, due to his knowledge of her sexual frigidity?

It is forbidden for the husband to touch his wife until he expiates the ẓihār if he uttered the word of prohibition upon her with the intention of temporary ẓihār. His ẓihār is then dissolved, and his wife becomes lawful for him upon the expiration of the period during which she was forbidden to him, without expiation. One should be cautious about uttering such words.