It was when Katara was at her strongest that Sokka was at his weakest.
Sokka loved Katara- she was his sister and practically his mother, and she put up with him and all his flaws for the 23 years that she had been alive. He loved Katara's little girl, too, Kya- bless that 4 year-old child for inheriting Aang's personality and all of Katara's waterbending prodigiousness. Spirits, he even loved Aang, annoyingly good as he can be sometimes.
When the full moon inevitably comes every month, however, he couldn't stand any of them. He couldn't stand any waterbenders. He couldn't stand the people that represented the reason Yue had to die.
He supposed Katara always knew, which must be why she tried to be as helpful as possible every full moon. He'd always been able to cope with it, but everything took a turn for the worse when he and Suki broke up.
"It's over."
"But…"
"I can't compete with a spirit. I can't compete with her- Yue."
"She's dead, Suki. You know that I love you-"
"Yes. Yes, I know you do… just not as much as you loved her, and I tried to deal with that, but it's too much, Sokka. I can't anymore."
That was three months ago… and every month, he had been condemned to stare longingly at the moon. I'll always be with you, Sokka. He wondered if she was watching him now, if she thought he was being pathetic. No, she doesn't. Yue was loving and sweet. She doesn't think anyone is pathetic.
Sokka sat up from the bed he was laying on and looked out the open window. The moon wasn't out. It- she- was hiding behind dark clouds. He crossed his arms behind his head and thought about the question he had been asking himself since she was transformed- why can't I get over her?
He supposed it was because she was the big question of his life. Yue was a what-if, and the torture of wanting to know the answer to that question was what made him hold on to the memory of her so tightly. What if she hadn't died? What if they broke up later on, like him and Suki? What if she still married Hahn? What if he and Yue got married? What if Katara had a niece or nephew to train along with Kya? What if, what if, what if…
All he wanted was answers to his incessant questions, and the necessity of waterbending had deprived him of those. Damn you, Katara, Kya, Aang, Pakku… damn all of you. Damn you, Iroh, for reminding her she was a child of the moon.
He sighed. Yue was a good person. She wouldn't have wanted him to be this angry, especially nine years after the event, but every time he saw a waterbender at her fullest capacity, all he could think about is whether they knew who had to die- who he had to let go of- in order for them to play with their waves.
The moon's out. Sokka stood up and reached his arms out, tried to touch the luminous moonlight… but, just like the princess, it slipped through his fingers. Another sigh. It just wasn't going to be possible, was it? I have to let go of her. Tonight. I have to start tonight. 9 years has been long enough.
For some inexplicable reason, his head's first idea of letting go was to ask Chief Beifong out for a drink in a nearby pub. I'm sure Toph can scare anyone into babysitting Lin, late as it is.
Turning away from that beautiful, unreachable white orb in the sky, Sokka walked off to see if his best friend wanted a break from bossing those loyal metalbenders around. Maybe Suki's right. Maybe I'll always love Yue. I guess I just need to find someone I'll love more.