The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fada'il Al-Sahabah)
Muslim :: Book 31 : Hadith 5975
'A'isha reported that Allah's Apostle (may peace be upon him) did not marry any other woman till her (Khadija's) death.