Why won't Edward change Bella in New Moon? He wanted to in number one, why not now? Nothing's changed.
Edward never wanted to change Bella, not even in the first book. So, you are right, nothing has changed. Edward regards himself as a monster, a thing of nightmares, and he doesn't want Bella, who he loves, to become like that. Creatures that have to kill and drink blood--it's not a pretty life to live. Because of the negative sides of being a vampire, he doesn't want to change Bella at all. Or course he wants to be with her forever, but he realizes that changing Bella is irreversible; it is forever. Once that step is taken, they can't take it back. He mentions in book two that he is worried about Bella's parents--they would grow and age, and she would always be the same. Also, getting changed changes one's appearances too; he knew that her parents would notice. She would have to leave, and that would be abandoning her parents. It would also keep her from a normal, happy life. So those are all of the reasons that Edward, from the beginning, doesn't want to change her, even though he wants to be with her always. I hope that helped; good luck!