Musnad Ahmad 1153:1586

Yahya narrated to us, Ubaydullah narrated to us, he said: I heard al-Qasim, or he narrated to me from Aisha, that a man divorced his wife three times, then another man married her and divorced her before he had touched her. The Messenger of Allah (peace and blessings of Allah be upon him) was asked: "Is she lawful for the first [husband]?" He said: "No, until he tastes her honey just as the first one tasted it."