Several reviewers noted this subtext. Some focused on the abstinence angle:
Abstinence is one example of Meyer's unrealistic romanticism. Another is how every youngster is paired up. Everyone has a date for the prom. I think Jacob and his fellow Indians are only ones who don't get love interests. Which is understandable because they're only semi-human werewolves, not real people with real lives.
Edward the stalker
Others reviewers focused on the potential for abuse. For instance:
Good point. Edward watches Bella, almost stalks here. He's paternalistic and knows best. If he thinks she can't handle something, he coolly tells her to go away.
Meanwhile, Bella is desperate and needy. She can't live without him and can't let go. She doesn't think to ask hard questions about dating a vampire, she just gives in.
She does indeed sound like a potential abuse victim. She trusts Edward not to go crazy and drink her blood because she knows he's "good." She doesn't ask how long he's been a "vegetarian" or whether he's ever slipped. Doesn't ask how he treated women in the past, whether they fought, or how they broke up.
Relationships like this don't work in the real world. The power between them is totally out of balance. Whenever they disagree about something, Bella will have to give in because he's the super-strong vampire and she isn't.
How is Edward the perpetual high-school student going to support a family? How can they have a normal life when vampires are always on the run? Suppose she wants a career or children...then what?
In "mixed" relationships like this, one party usually has to convert to the other's side. It's patently obvious that Bella will demand the vampire venom sooner or later. Then what? Does she bite her loved ones (father, mother, et al.) so they can live forever too?
I know little girls dream of being swept off to castles where they can live as princesses happily (for)ever after. That explains why Twilight has the tween demographic sewn up. I'm not sure what it has to offer adults who prefer real-world relationships to fairy tales.
For more on the subject, see Romance in Twilight Movie.