Disclaimer: It seems like people would know that this is FANFICTION and nobody is the real creator/author of whatever we're writing about. But anyway, I don't own Avatar.
Oh, and I believe that this is a scientific fact, though I'm not sure what the details of it are.
They say that some types of female spiders will kill their mate (which can be translated to boyfriend) after a while, perhaps growing tired of them, or maybe getting angry at them for destroying the web.
Zuko was sure that this was his fate when he kissed Katara for the first time. In his twisted and slightly childish way, he thought that a first kiss was a big deal to girls and that Katara would get very angry with him.
But he was quite surprised when it wasn't a slap that he received, but a kiss in return, a smirk, and a "Don't worry, that wasn't my first kiss," that left him speechless and embarrassed, for it had been his.
Poor Zuko. Who knew that Katara had had several boyfriends before him, including Jet, Haru, and Aang. (though I'm not a Kataang fan)
This is probably my shortest fic so far.