[Bella:] I wanted the complete experience before I traded in my warm, breakable, pheromone-riddled body. (1.204)
Bella believes that, as a vampire, she won't feel the same physical attraction to Edward than she does in her human body.
[Bella:] "I never got over the shock of how perfect his body was – white, cool, and polished as marble." (2.16)
A big part of Bella's attraction for Edward is due to his looks.
[Edward to Bella:] "You should be angry at me" [Bella:] "Well, I am"… "That," I snapped. "That right there is why I'm angry. You are killing my buzz, Edward." (5.155-158)
Bella doesn't care that Edward bruised her during lovemaking; she wants him to let go and enjoy being with her without castigating himself over his lack of self-control.
[Bella to Edward:] "I just was trying to explain that, for a human, well, I can't imagine that life gets any better than that." (5.168)
Bella seems to believe the lovemaking is the epitome of human life. What's your take on that?
[Edward to Bella:] "I spoke to my brothers, too. They told me that it was a very great pleasure… Second only to drinking human blood (5.175)
For a vampire, drinking blood is still the greatest pleasure. What pleasure in our human life might compare to how a vampire feels about drinking blood?
[Bella:] "I started slow with innocent ivory satins, worried that revealing more of my skin would be the opposite of helpful, but ready to try anything." (6.8)
Bella struggles with her burning desire to seduce Edward and her knowledge that she needs to hide her intentions as much as she can.
[Bella to Edward:] "I like this part of being human. I don't want to give it up yet. I don't want to wait through years of being blood-crazed newborn for some part of this to come back to me." (6.38)
Bella believes that a big part of her physical and emotional attraction toward Edward will disappear when she transforms into a newborn vampire.
[Bella:] "It wasn't desire at all – it was need, acute to the point of pain." (6.86)
Bella's desire, her physical need for being with Edward, has become so strong that it causes her pain.
[Bella:] "I could see their ruby eyes glinting with desire, lusting for the kill." (7.1)
Bella connects lust, or sexual desire, with the desire to kill. What might these two urges have in common?
[Bella to Edward:] "I thought I wouldn't feel this way for a long time… But I still want you." (21.128)
Bella realizes that – against all predictions – her transformation into a vampire hasn't lessened her sexual attraction for Edward.