In Islam, it is not permissible for a wife to breastfeed her husband. Breastfeeding in Islam is specifically for establishing a mahram (legal) relationship between a nursing mother and the child she feeds. This relationship prohibits marriage between them in the future.
The Quran outlines a clear time frame for breastfeeding, which is the first two years of a child's life. Beyond that, even the child's own mother cannot breastfeed them anymore.
While a wife may produce breastmilk, its purpose is for nourishing her children, not for creating a mahram relationship with her husband. Such an act would be considered a great sin in Islam, and it is not recognized as a valid way to establish a mahram relationship.
References:
- "No woman can produce breastmilk on demand whenever she wants to make someone her non-Mahram".
- "The husband does not become haram upon the wife by taking in the milk of the wife. However, it is a great sin for the husband to take in the milk of his wife."
- "Drinking one's wife's milk has no effect and does not create such a relationship because the breastfeeding which has an effect is that which..."