The painted veil - W. Somerset Maugham

Kitty Fane is the beautiful but shallow wife of Walter, a bacteriologist stationed in Hong Kong. Unsatisfied by her marriage, she starts an affair with the charming, attractive and exciting Charles Townsend. But when Walter discovers her deception, he issues her with a strange and terrible ultimatium: Kitty must choose between publicly humiliating divorce, or accompanying him to his new posting in remote mainland China, where a cholera epidemic rages.