What happens when a new guy comes on the scene and changes the way everyone relates to each other? Visit thisamericanlife.org/lifepartners to sign up for our premium subscription. Prologue: Ira talks with Sarah Koenig about the first and only time a movie star came to her family's house when she was a kid. It didn't go well, for the celebrity or for her. The star was Robert Redford. He arrived and immediately stole all the attention her parents usually lavished on her, their youngest. Worse, they were nervous and strange around him, not themselves at all. Young Sarah was not pleased. Robert Redford paid the price. (6 minutes) Act One: Davy Rothbart's mother is funny, rational, and by most measures, pretty normal. Except that she spends every day in the company of an ancient Buddhist monk named Aaron, who no one else can see. Davy talks to his brothers, father, and eventually his mom, and asks the question they've somehow never managed to discuss: do any of them actually believe he's real?…