Is sexual intercourse permissible if the necessity can only be averted by invalidating the fast of another person?
General Chapter
Al-Mughni
Book of Fasting
Primary text
If the necessity cannot be resolved except by invalidating the fast of another, then it is permitted. This is because it is something necessitated by the circumstance, thus it is permitted just like the initial breaking of the fast, similar to how pregnant and nursing women are permitted to break their fast out of fear for their offspring.
Supporting text
If a man has two wives—one menstruating and one clean and fasting—and necessity drives him to intercourse with one of them, there are two scholarly perspectives. One view holds that intercourse with the fasting woman is preferable because Allah explicitly forbade intercourse with a menstruating woman in the Quran, and the harm caused by intercourse with her does not cease with the need for intercourse. The second view holds that he has a choice because intercourse with the fasting woman invalidates her fast, leading to a conflict of two harms, rendering them equal.