Behind Her Eyes by Sarah Pinborough

Psychiatrist David and his beautiful wife, Adele, move to London to try and put the past behind them. However, after David kisses his receptionist, Louise, and appears to restrict Adele's movements by checking in with her a couple of times a day and watching her spending habits, their relationship seems to be heading in the same awful direction as before. When Louise and Adele become friends without David's knowledge, the triangle of their relationships becomes even more complex and disturbing.  Is Louise just a pawn--and can she really trust either David or Adele? Behind Her Eyes is a fast-paced novel that will appeal to readers of The Girl on the Train. It also has a truly unexpected ending.