I know that when I’m writing, and I’m “inspired” by someone or something, I’m usually referring to a specific aspect or trait, which I will then heighten for whatever fictional character I’m creating.
For example, she might, say, be inspired by his stoic demeanor while slaying a bathroom spider and use that in a book she’s writing about a knight fighting a dragon. Using someone as inspiration isn’t the same as casting. And that’s why he might be surprised, too. He might not see himself in the sexy rogues she writes about, but because she loves him, she clearly does.