Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: A woman accepted Islam in the time of the Prophet (peace and blessings be upon him). Then her first husband came to the Messenger of Allah (peace and blessings be upon him) and said: "I accepted Islam along with her, and she knew of my accepting Islam." So the Prophet (peace and blessings be upon him) took her from her later husband and returned her to her first husband.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11671