The Age of Innocence (Broché)

Upper-class New York gentleman Newland Archer is set to wed May Welland in a picture-perfect union when the bride's cousin, Ellen Olenska, returns from a failed marriage overseas. As Newland endeavors to help Countess Olenska be reinstated into the family's good graces, his affections for her grow. Newland soon finds himself torn between his desire to conform to the society he knows and his new-found passion for the forbidden Countess.
The Age of Innocence was originally published in 1920 as a four-part series in Pictoral Review, then later that same year as Wharton's twelfth novel. It went on to win the 1921 Pulitzer Prize for Fiction, making Wharton the first woman to win the award.