Sokka
"So this is your girlfriend. No wonder she left, she's way too pretty for you."
Every time they saw Zuko after the run-in with the bounty hunter Sokka kept remembering what she'd said.
It was silly, Sokka knew that, but he was a paranoid sort of older brohter. Just the mental imagery, just the idea was scary enough. The mere suggestion…
Oh yeah right. The day Katara dated a firebender would be the date Sokka danced naked in a field of daisies.
Still… he snuck a glance at his sister over the campfire. She did have that horrible habit of picking up strays.
There was Jet. And the Earthbender with the pretty-boy hair. The starving lost kitten two weeks ago. Even Aang kind of counted.
"Katara, hypothetically speaking, would you ever date—"
"Oh give it up Sokka!"