Even though musicologists have tended to gloss over Piotr Illyich Tchaikovsky’s sexuality, it’s generally acknowledged that he prefered the company of men. Remembered most for his ballets (Swan Lake & The Nutcracker) and The 1812 Overture, his 6th Symphony (The Pathetique) is infamous for its dedication to his nephew (pictured on the right with his uncle), with whom Tchaikovsky was intensely in love.
An excerpt from an 1892 letter to his nephew: “I often think of you and see you in my dreams, usually looking sad and depressed. This has added a feeling of compassion to my love for you and makes me love you even more. Oh God! How I want to see you this very minute.”
Great collection of his intense letters to his nephew on a site linked above.