By Nightfall by Michael Cunningham

A middle-aged, cultured art critic leading a stable family life becomes captivated by a charismatic young photographer whose presence and ambitions ignite an affair and a cascade of moral compromises; as secrets surface, he must confront the tension between aestheticizing life and ethical responsibility, putting his marriage and identity at stake and prompting a painful reassessment of desire, loyalty, and self-deception.

Purchase from Bookshop.org