Musnad Ahmad 1153:2368

'Amir ibn Salih narrated to us, he said: Hisham ibn 'Urwah narrated to me, from his father, from 'Aishah, she said: "I did not feel jealous of any woman for the Messenger of Allah, peace and blessings of Allah be upon him, as I felt jealous of Khadijah, and that was because of what I used to hear of his mentioning her."