5x18 - 7th Heaven

The striking resemblance of Robbie's new friend, Marie, to Mary raises eyebrows among discerning Camdens. Annie's invitation for her to stay for dinner makes things weirder for them. Back in Buffalo, unbeknownst to Robbie, Mary accidently bumps into her old boyfriend Wilson (guest-star Andrew Keegan) and his son Billy at the train station and makes plans to meet him for the evening. Mary is unsure on whether she should tell Robbie, but confides in her family about this. They all say that she should tell Robbie about this, but decides to ignore their advice. Also, Matt meets Robbie's ex-girlfriend, Cheryl, at the restaurant where she works. He starts to have feelings for Cheryl and tries his best to try to get her to go on a date with him. His efforts work by the end, but is having a hard time telling Robbie about his interest in his ex-girlfriend.