Being in love with someone who has to constantly fight the urge to eat you is not sexy.
Typical Vampire folklore states that Vamps burst into flames when they step into the sunlight. It's a cliche fact at this point but a cool cliche that's probably not worth switching up. However, in the Twilight Saga, while the Vampires can step into the sunlight, it's not a favorable decision because instead of bursting into flames their skin sparkles like diamonds. Um...scary?
Bella and Edward went to sunny Brazil for their honeymoon despite the fact that Vamps in this series don't step into sunlight because their skin glows. Blank stare.
The female Vampires in Twilight can't pro-create but the men can spread their seeds. However, it can be dangerous. When mortal women are pregnant with Vamp spawn the gestational period pretty much lasts for a day and is usually a guaranteed fatality for the mother. A 24 hour pregnancy? That would be nice if you didn't have to die. What part of the game is that?
The only way to kill Vampires is to tear them to shreds and burn the pieces. This is so extra. What happened to a good ol' stake in the heart?