Musnad Ahmad 1153:634

'Affan narrated to us, Hammad ibn Salamah narrated to us, he said: 'Ali ibn Zayd informed us, from Umm Muhammad, from 'Aishah, that the Prophet (may Allah bless him and grant him peace) said regarding a man who divorced his wife three times, then another man married her, then divorced her before he had touched her: "The first [husband] shall not remarry her until she tastes his sweetness, and he tastes her sweetness."