Yes, even someone as... special as Richard Wagner has one. After the birth of their son, Siegfried, Wagner composed a tender musical poem to his wife Cosima, the "Siegfried-Idyll," awakening her with it on the morning of her birthday, December 24, 1870. He would later use the opening theme of the work in Siegfried itself to represent Brünnhilde as the Immortal Beloved awakened by the eponymous hero.
He was one of the few people who believed in composer Anton Bruckner, and when Bruckner was depressed due to the harrowing reception of his work, Wagner hugged him and told him he loved his work. A life-long friendship with mutual respect ensued.