Aang had to detatch himself from earthly things (katara) in order to go into the avatar state. And this concept can't just be ignored because this was the very reason why ba sing se was given over, because aang couldn't go into the avatar state untill he went into the crystal cacoon thing and gave up katara then went into the avatar state. Sooooo, why was aang able to go inot the avatar state with still being attatched to katara, same goes for the water tribe avatar who lost his women to that face stealing spirit and roku with being able to go into the avatar state with having a wife.