Khadijah passed away three years before the Prophet's ﷺ departure. He remained for about two years or so, then he married Ayesha when she was six years old, and consummated the marriage with her when she was nine.
توفيت خديجة قبل مخرج النبي ﷺ بثلاث سنين، فلبث سنتين أو قريبا من ذلك ونكح عائشة وهي بنت ست سنين، ثم بنى بها وهي بنت تسع سنين.
Bukhari narrated it in the Book of Virtues (3896) from Ubayd bin Ismail, who said, Abu Usama narrated to us, from Hisham, from his father, who said, and then he related it. Its apparent form is mursal, but it seems most likely that he heard it from Ayesha.