Urwah bin al-Zubayr (may Allah have mercy on him) said that a slave woman of Banu Adi bin Ka'b who was called Zabra' told him that she was married to a slave, and she was a Nubian slave woman. She was freed, so she sent word to Sayyidah Hafsah (may Allah be pleased with her), the wife of the Prophet (peace and blessings be upon him), who called me and said: "I am going to tell you something, and I do not like you to do anything: your matter is in your own hands as long as your husband has not had intercourse with you." She said: So I separated from him with three (divorces).
(b) Abu Qilabah (may Allah have mercy on him) said that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said: "Once he has had intercourse with her, the slave woman no longer has the choice."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14286