“Nina: Why she wouldn’t date any of her co-stars.” She’s now the cover girl of October’s Seventeen and is doing exactly that, dating co-star Ian Somerhalder. “It was honestly what I believed at the time,” says Dobrev. “I didn’t want to be. and yet our characters are still dating on the show. It’s a good thing it’s not awkward! Well, it’s a good thing we have chemistry!" The Vampire Diaries…