How sound is the attribution of the saying "I was blessed with her love" to the Prophet, peace and blessings be upon him, concerning Aisha, may God be pleased with her, and what is the ruling on changing it to "I was blessed with his love" for use in gifts?

The phrase "Indeed, I have been blessed with her love" was spoken by the Prophet, peace and blessings be upon him, concerning Khadijah. This does not negate that he was also blessed with the love of Aisha, as he was asked who was most beloved to him, and he replied: Aisha.

There is no objection to writing this phrase on fabric and gifting it to one's wife, or vice versa, provided that the writing is not subjected to disrespect.