Can't find a specific gay love stpry Help!

The story involves a pilot crashing in the wilderness and being rescued by a quiet/mysterious bear? He finds out the man is a veteran that fled humanity after a tramatic experience as a soldier they make love. The pilot goes back to his life but leaves a message for his rescuer in a book. I just really loved the story and want to reread it. I've been looking so long at this point it's become an obsession of just finding it again. Does anyone know the name of it?