She sees herself in her own memory, hears her own voice as a stranger might, saying, "Aang, can the people of Ba Sing Se wait? I'm exhausted and," she gestures to the toddler snuggled in a sling in her arms, "I have just met my niece for the first time, and it's her third birthday," She remembers the way the wind blew up a gust, and how the beginning curl of anger warmed her. Oddly enough, her memory can't bring up his face, just the strain of his voice as he says, "But there are people out there who need us, Katara. Really need us."
She tenses and responds, "But the people here need us too. My family needs us, just in a different way." And she's finally saying it, all the things they've been tiptoeing around for years now, the regrets and disappointments she's been swallowing in order to make his dreams possible, "This pregnancy has been harder for Suki (and I wasn't here last time), and my dad needs a waterbender to teach (since Master Pakku died in his sleep), and, Aang…" and now she can remember the look in his eyes, that dreadful hardness to them, like he wasn't even seeing her anymore, but she plunges on "—I know the world is important, but isn't the South Pole important too?"
(The question hangs between them – aren't I important too?)
She takes a breath to continue, but is stopped when he quietly breathes out the words, "I don't know anymore."
"What?"
"I don't know if I can take this anymore. I thought it would be so different. Maybe it would be better if I went alone. Permanently."
Silence blossoms between them, and Katara can remember the way the snow started to fall, gently, and she hears her own voice as an outsider, "So that's it. You're just going to leave? Ba Sing Se needs you, so you go?"
He gives a curt nod, and turns away.
The pain in her chest gives way to blind fury, and her voice can barely contain it as she steps toward him, "After everything? This is how you're ending it?"
He looks at her with tenderness then, but it's the tenderness of condescension, of him-knowing-better, "It's for the best this way. Maybe some day we can meet as friends." And with those trite words, he's off on his glider, flying through the cloudy skies towards the village.
In her memory, she stands there only a moment before Sokka comes cresting over the hill, joyful about his new meat find, until he sees her, and, in a moment, is running to wrap her in his arms.
A/N: Just re-watched AtLA and was struck by how selfish Aang is through most of the series. Given that, I wanted to write something where he breaks it off with Katara because he can't accept that she has needs different from his. Let me know what you think!