Sahih Muslim 708
صحيح مسلم#708SahihAnas reported:The Messenger of Allah (ﷺ) used to have sexual intercourse with his wives with a single bath
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 3:30