I think it's very brave of Nabokov to place himself in the shoes of a personality in which society finds not only immoral, but outright disgusting. He did an excellent job as well. The pedophile tries to justify his actions, calling it true love. Although at first glance you may think the author is on the side of the pedophile, he shows the abusive nature of the relationship; the pedophile becomes very possessive and even desperate at times when he feels he lost control.
I don't have anything else to say about that.