Don't Let Him In, Paperback/Lisa Jewell

He's the perfect man. He says he loves you. You think he might even be made for you. Before long he's moved into your house - and into your heart. And then he leaves for days at a time. You don't know where he's gone or who he's with. And you realise - if you looked back - you'd say to yourself-DON'T LET HIM IN.