Behind her eyes / Sarah Pinborough.

"Only two can keep a secret if one of them is dead. David and Adele seem like the ideal pair. He's a successful psychiatrist, she is his picture-perfect wife who adores him. But why is he so controlling? And why is she keeping things hidden? As Louise, David's new secretary, is drawn into their orbit, she uncovers more puzzling questions than answers. The only thing that is crystal clear is that something in this marriage is very, very wrong. But Louise can't guess how wrong--and how far a person might go to protect their marriage's secrets. "--