sentences:  At a furniture show, the pair run into Natasha and Big, who confides to Carrie that he made a mistake marrying Natasha and wants out.Soon afterward, Big and Carrie begin an affair, which ends only when Natasha catches Carrie at Big's apartment.Wracked with guilt, Carrie tells Aidan of the affair on the day of Charlotte's wedding to Trey, and Aidan breaks up with her.