Is it permissible for a man to imagine having intercourse with another woman (married or unmarried) during coitus, and is he forbidden from having intercourse with his wife in this situation, by analogy with the prohibition of drinking water if one imagines it to be wine?

Scholars have differed on the permissibility of a man imagining, during intercourse with his wife, that he is having intercourse with a foreign woman. Those who prohibited it relied on evidence, including the analogy of imagining water to be wine. The correct approach is to avoid such imagination, based on the Prophet's (peace and blessings be upon him) saying: "Leave that which makes you doubt for that which does not make you doubt." According to both opinions, the wife does not become unlawful to her husband. What is prohibited, according to those who deem it so, is the imagination itself, not the wife.