Sunan At-Tirmidhi

Narrated 'Aishah:""I was not jealous of any wife of the Prophet (ﷺ) as I was jealous of Khadijah, and it was not because I did not see her. It was only because the Messenger of Allah (ﷺ) mentioned her so much, and because whenever he would slaughter a sheep, he would look for Khadijah's friends to gift them some of it