By Lily Calandra It's Thursday night. The television is murmuring in the background, but you aren't watching it. You are watching the front door, listening for the sound of keys, your chest tightening with the exact same question that kept you awake last week: What version of them is coming home tonight? Or maybe they are sitting right next to you on the couch, but as they pour another drink, the distance between you feels like a canyon. You love them. You have a history together. But you...