What is the theme in Dark Flame by Alyson Noel?

Light versus dark is a theme. In this novel, Ever finds herself magically bonded to Roman in a way that makes her act in ways that she might not otherwise. Ever is desperate to break this bond because she does not want to be with Roman, she does not even like Roman. However, the more Ever fights this bond, the more intense it becomes. Finally it comes to the point in which Ever begins to lose her power and her beauty and health that come with immortality begin to fade.