The great Love and fidelity between Our beloved prophet and his first wife Khadija
Aisha narrates: "Whenever, Prophet Muhammad (saw) slaughtered a lamb he would say: 'Send this to friends of Khadijah.' Once I asked for the reason of this action and he (saw) replied: 'I like friends of Khadijah as well.'"
After Lady Khadija (sa) demise, Prophet Muhammad (saw) regarded her many times as a great woman. Once, years after Lady Khadija (sa) died, Prophet Muhammad (saw) came across a necklace that she once wore. When he saw it, he remembered her and began to cry and mourn. His love for her never died, so much so, that his later wife Aisha became jealous of her. Once she asked the Prophet Muhammad (saw) if Khadijah (sa) had been the only woman worthy of his love. The Prophet Muhammad (saw) replied: "She believed in me when no one else did; she accepted Islam when people rejected me; and she helped and comforted me when there was no one else to lend me a helping hand."
Prophet Muhammad (saw) always remembered Khadija and moaned, "Never did Allah (SWT) give me a better wife than Khadijah. She hailed my mission at a time when everybody shouted against it. She lent me the support of her conviction when there was hardly a believer. She enlivened my heart when I felt lonely and deserted. Khadijah's love was given to me by Allah (SWT). How could I forget her?"
Narrated Aisha: Once Hala bint Khuwaylid, Khadija's sister, asked the permission of Prophet to enter. On that, the Prophet remembered the way Khadija used to ask permission, and that upset him. He said, "O Allah! Hala!" So I became jealous and said, "What makes you remember an old woman amongst the old women of Quraish an old woman (with a toothless mouth) of red gums who died long ago, and in whose place Allah has given you somebody better than her?"
Prophet Muhammad (saw) became very angry at this
Moreover, al-Bukhari narrated that Aisha confessed: Sahih Bukhari Hadith: Volume 5, Book 58, Number 166:
I did not feel jealous of any of the wives of Prophet as much as I did of Khadija though I did not see her, but the Prophet used to mention her very often, and when ever he slaughtered a sheep, he would cut its parts and send them to the women friends of Khadija.