The Painted Veil by W. Somerset Maugham
Walter and Kitty Fane are posted in Hong Kong, he a bacteriologist, she a socialite who married him because it was time to marry somebody and no one else was showing any interest. She quickly becomes bored and has an affair with the utterly charming, utterly shallow, utterly married, Charles Townsend. When Walter, who truly loves her, finds out about it, he offers her a choice: he will divorce her if Charles will marry her, or she can forget Charles and go with her husband to his new posting in a remote village overrun with cholera.
Kitty goes to Charles, expecting him to assure her of his undying love, and is horrified to find that he wants her to go with Walter. He has no intention of leaving his wife and children for Kitty, so to him, this looks like the perfect solution. Defeated, Kitty goes.
In the village, Kitty gets involved with the nuns who nurse the sick and provide a home for orphaned children. This is a setting in which she is forced to look outside of herself and she begins to grow up a little, then she meets up with Charles again.
Kitty will leave you shaking your head. She reminds me of Scarlet O'Hara with her drama and inability to make a wise decision, but she does learn and grow over time, finally becoming someone you can hope is going on to live a better life.
I enjoy Maugham's writing. I loved it in "Of Human Bondage", though the main character in that nearly drove me crazy with shooting himself in the foot over and over again - and I loved it in this book. His dialogue is natural and flows well, and he builds characters with both strengths and weaknesses, portraying human frailty particularly well.
The Painted Veil is worth reading, and it's a small book so it won't require much of a time investment if you decide to give it a try.