It is narrated from Hazrat Salamah (may Allah be pleased with him) that if a person committed adultery with his wife's slave-girl, the Prophet (peace and blessings be upon him) said: If he forced the slave-girl into this act, then she will be set free and the man will be liable to pay her the equivalent of a dowry. And if this act was done with her consent, then she will remain his slave-girl, but the man will still have to pay the equivalent of a dowry.