Bumping into a teenage sweetheart can be jarring. Do you feel a twinge of nostalgia, the stirring of old emotions as you notice puppy fat has disappeared to reveal a strong bone structure? Or do you internally cringe, turn and walk the other way? [Warning: spoilers ahead] For Lily Bloom, in Colleen Hoover’s much-adored novel It Ends With Us, running into her first love Atlas reignites a fizz of buried feelings. The book, which has been adapted for screen starring Blake Lively and Brandon...