Rereading Lolita you catch the hints that point to Humbert's monstrousness; you see the bread crumbs left by Nabokov which lead back to the world of morality. Humbert fixes himself up with several defenses: she seduced him, age of consent is arbitrary (Humbert regularly invokes Dante and Beatrice, Plutarch and his young lover but always leaves out that yes, the lovers were children but so were Dante and Plutarch -- a far cry from little Lo and middle-aged Humbert), she was a stupid brat anyway (a close reading will catch her intelligence and survival instincts), followers of Freud will blame Humbert's coitus interupptus with young Annabel Leigh for his lunacy (Humbert quickly falters on that one and mocks "Herr Doktar" from the beginning), still others will see Lolita as a great love story (ugh).
Although there is definitely something strange going on if a reader believes that a twelve year old child who has been kidnapped and raped repeatedly somehow was compliant but Humbert is very convincing and a reader can be forgiven (with raised eyebrows) for believing any of his defenses; even my beloved Robertson Davies believed that Humbert was the victim of an evil child who exploited his love and Vanity Fair calls Lolita "The only convincing love story of our century" (I don't... I don't even know...).
It is upon rereading (which Nabokov spent his life stressing the importance of, driving it home in all of his novels) when the reader notices the cracks in the facade. Lo cries herself to sleep every night (he never asks why -- not much of a caring lover is he?). She doesn't know what sex is when she 'seduces' him. She leaves him on Independence Day. Humbert feels remorse and acknowledges, at the end, that he "broke her life".
The reader must remember, the re-reader too, that everything we are told is from Humbert, he is the narrator and an unreliable one at that, as is made clear time and time again with brief snippets of dialogue between him and Lo.
Humbert is a vile monster, a predator who kidnaps an orphaned child and holds her captive for two years, raping her constantly. There is no excuse for this, no defense; perhaps the audience's willingness to lay some of the blame on Lo stems from our culture of rape, where the survivor is always responsible for their attack, how else to explain any ambiguity in the interpretation of Humbert Humbert? Or is it because in the movies Lo is always very sexual and decidedly pubescent? In the novel Lo is a kid, a pre-teen, pre-pubescent with no great skill of seduction because she is a child who does kid things like shun cleanliness and read comic books. The movies and the book covers misrepresent Lo as a sexy teenager when she was hapless kid.
Lolita has entered our vernacular as a term to describe over-sexed teenagers; missing the point entirely that she was in fact a victim of sexual predators, pedophiles. In fetishizing Lo, the audience has absolved Humbert of any guilt.
The greatest disappointment of Nabokov's life was that the book was so widely misinterpreted, but banking on re-readers was a mistake which helped cause generations of readers to believe in Humbert's innocence, the other mistake was thinking that a patriarchal society would ever sympathize with a female rape-victim.
Lolita is one of the funniest, most perfectly wrought novels and every reader owes it to themselves to read it, then reread it, then reread it again -- there is something to be gleaned every time. This novel will enhance life, it will sharpen the senses and inspire greatness -- sweet fancy Moses, it is incredible but it is not a love story!