Family Matters...

I was rewatching it, and by the looks of it Zuko's mom ran away. That, or she was sent away. When I began to think about why in the world she would do such a thing, I came upon a theory. What if Azula is Zuko's half-sister. I mean, Ozai could've had a lot of wives. Then that would mean that whichever child Ozai thought best of could become the chosen heir and the mother the queen. If this was true, what if Azula's mom hated Zuko's and had her sent away afterward? Seeing as Nickelodeon aims this as a kid show, it may not be likely, but hey, who knows?