"Is she permissible for the first (husband to remarry her)?" He said: "No, not until he tastes her sweetness as the first tasted her sweetness."
Sunan an-Nasa'i Book 27, Hadith 24
← Previous Hadith "The wife of Rifa'ah came to the Messenger of Allah and said: 'My husband divorced me and made it irrevocable. After that I married 'Abdur-Rahman bin Az-Zabir and what he has is like the fringe of a garment.' The Messenger of Allah smiled and said: 'Perhaps you want to go back to Rifa'ah? No, not until he tastes your sweetness and you taste his sweetness.'"

Sunan an-Nasa'i Book 27, Hadith 23 Next Hadith → "O Messenger of Allah, she is lying; he is having intercourse with her, but she wants to go back to her first husband." The Messenger of Allah said: "She cannot do that until she tastes his sweetness."

Sunan an-Nasa'i Book 27, Hadith 25