It was narrated from Ibn 'Abbas that:
a woman came to the Prophet and became Muslim, and a man married her. Then her first husband came and said: "O Messenger of Allah, I became Muslim with her, and she knew that I was Muslim." So the Messenger of Allah took her away from her second husband and returned her to her first husband. (DE)
English reference (DE): Vol. 3, Book 9, Hadith 2008 (DE)
Arabic reference (DE): Book 9, Hadith 2086 (DE)