Isn’t the Buffy/Angel relationship basically the same as Edward/Bella?
While the two pairings may share some similar narrative elements, I think the relationship dynamics are actually very different in terms of narrative lessons and messages (I would argue they are almost complete opposites in fact). As an example you can compare the original vampire stalking clips from both Buffy and Twilight for yourself on the Critical Commons website – and read my commentary on the topic there.