He Stopped Loving Her Today (George Jones)
"I'll always love you."
"No, Dean. That is the beautiful thing about humans. You will forget me, in time." Castiel smiled at the man he had claimed to love for so long. "Goodbye, Dean."
"I'll wait for you." Dean spoke to an empty room- the angel had already left with a barely-there flutter of wings. And wait Dean did. For years, Dean waited faithfully for the return of his angel, despite everyone telling him to just let the man go. Dean refused, simply replying with
"I love him." whenever anyone, including his baby brother Sam, asked his why he didn't go out with her or him. "He'll be back." Dean didn't know that anyone knew, but he kept little momentos of the angel all around his house. A feather in the knife drawer, a hasty Enochian translation in the top drawer of his desk. A picture of the two of them, smiling, arms wrapped tight around on another, under his pillow. Dean never gave up hope, and prayed to his angel every night. Sometimes, though, he got lonely. He'd drink the night away, then rave to the skies for Cas to come down and see him before he did something... drastic. But still, no angel appeared. Dean never loved again.
"You have no right." Sam Winchester was visibly angry. "Get the hell away from here. He's over you for good this time." Castiel didn't speak to the angry man, simply looked around him to the body burning on a Hunter's Pyre behind him. Dean had been killed, had made it longer than anyone expected. Dean lived well into his 50s, but never let Cas out of his heart. For a long moment, Castiel simply stared at the bright, burning fire. He finally turned his gaze to the large man practically vibrating with anger in front of him.
"I'm sorry for your loss, Sam." The angel's voice was flat, unemotional. This just made the Winchester in front of his even more livid.
"Dammit, Castiel! If you don't care that he's dead then why the hell are you here? Come to rub it in his face one last time that he'll never get over you? Well he did, dammit. Let his be happy for once in his life. I haven't seen him smile since you walked out on him, you asshole." Castiel's response wasn't verbal. He just looked at Sam for a long time, allowing his pain at the green-eyed hunter's death to fill his eyes before disappearing, never to see either Winchester again.
A few days later, at the sight of the fire, Castiel stood, staring at the burn mark his hunter had left upon the forest floor.
"You were supposed to let me go, you know." He knew Dean couldn't hear him- that's the only reason he allowed himself to speak to the deceased hunter. "You were supposed to move on and be happy. I knew I wasn't any good for you. You stubborn man. I just wanted you to be happy." Castiel scowled. "You were supposed to be happy."