Musannaf Ibn Abi Shayba 7:388

Ad-Dahhak ibn Makhlad narrated to us, from Ibn Jurayj, from Ibn Tawus, from his father, who said: If the one who performs *zihar* (the husband who likens his wife to the back of his mother) says, "I have no need of her," he is not left alone until he either divorces or performs the expiation.