All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Many interpreters of the Quran stated that the Prophet Yoosuf (Joseph) married the wife of Al-‘Azeez after her husband died. This narration is reported by Abu Al-Shaykh from Zayd ibn Aslam and its wording is that Yoosuf married the wife of Al-‘Azeez and he found her virgin as her husband was impotent. However, this narration is not authentic from the Prophet and it might be that it was taken from the People of the Book.
In any case, a Muslim does not need to know whether or not Yoosuf married the wife of Al-‘Azeez.
There is no excellence for Yoosuf in marrying Zulaykhah, as he was the generous, son of the generous (Ya’qoob [Jocob] ), son of the generous (Ishaaq [Isaac] ).
Allaah Knows best.