Getting Rid of Matthew by Jane Fallon

Helen is almost forty and has been having an affair with Matthew for four years. She realizes that she needs to make some changes in her life: get a new job and a new boyfriend. Of course, this is just the moment that Matthew announces that he's left his family for her. What can Helen do except let him move in? Helen (under another identity) then befriends Matthew's wife Sophie and comes up with the perfect plan to get them back together so she'll be off the hook. However, things get complicated when Helen falls for Matthew's son, Leo and her friendship with Sophie is real. Getting Rid of Matthew is a humorous, frothy story with a main character that could be Bridget Jones' older sis.