In David Koepp’s new thriller You Should Have Left, Amanda Seyfried plays Susanna, a young actress who, just before filming a big part in England, escapes to the Welsh countryside with her older husband Theo (Kevin Bacon). While inside the starkly modernist house (it could easily sit next to The Invisible Man’s spartan abode), secrets from their past start to show themselves in startling, sometimes phantasmagoric ways. It’s the rare haunted house movie where the characters are just as haunted. And it’s the rare Hollywood movie to address the significant age difference between the two leads. …