How we cite our quotes:
[Edward to Bella:] "I told you, most of those human desires are there, just hidden behind more powerful desires." (14.279)
Though Edward has sexual desires, he seems to be saying that his vampire thirst is a bit stronger of a "hunger," at this point.
[Edward to Bella:] "I don't think that…that…would be possible for us." (14.284)
Edward doesn't think they'll ever be able to have sex. But he seems to be OK with that. Mostly, he just enjoys being near Bella.
[Edward to Bella:] "That's certainly a problem. But that's not what I was thinking of. It's just that you are so soft, so fragile. I have to mind my actions every moment that we're together so that I don't hurt you. I could kill you quite easily, Bella, simply by accident." (14.286)
Edward thinks they shouldn't have sex because he's afraid he'll accidentally kill her.