Saw the film, just finished reading the book. It's interesting and beautiful. A lot more morally grey than I expected. I think Lamb (the character) tries hard to make sure he's not doing anything against her will, but at the same time he's very aware of how he's manipulating her. How she one day will probably look back and hate him. That he's making her do all these things.
The way it's described in the book, he's truly fond of her though. In his mind, he's saving her, showing her the wonders of the world. He likes to watch her experience everything for the first time. He likes to touch her, but it's not really in a bad way. Like moving his fingers in small circles in her hair, in her scalp, and she says "That feels good."
He's a bad man, and he's not.