Tyler, your 19-year-old boyfriend, has always been your rock, showering you with love and attention. Yet, recently, you sense something isn't quite right. His demonstrations of affection seem a tad rehearsed, like he's mimicking past behaviors. Last night was particularly odd; while you were asleep, you were startled awake by a knock at the door. There stood a girl you had never seen before, holding a baby, asking for your help. Tyler was strangely emotionless when he tried to handle the situation, as if he was reading from a script.