The Painted Veil by William Somerset Maugham

Kitty had a queer feeling that she was growing. The constant occupation distracted her mind and the glimpses she had of other lives and other outlooks awakened her imagination. She began to regain her spirits; she felt better and stronger. It had seemed to her that she could do nothing now but weep; but to her surprise, and not a little to her confusion, she caught herself laughing at this and that. It began to seem quite natural to live in the midst of a terrible epidemic. She knew that people were dying to the right and left of her, but she ceased very much to think of it. The Mother Superior had forbidden her to go into the infirmaries and the closed doors excited her curiosity. She would have liked to peep in, but could not do so without being seen, and she did not know what punishment the Mother Superior would inflict upon her. It would be dreadful to be sent away. She was devoted to the children now and they would miss her if she went; in fact she did not know what they would do without her.

And one day it occurred to her that she had neither thought of Charles Townsend nor dreamt of him for a week. Her heart gave a sudden thud against her ribs: she was cured. She could think of him now with indifference. She loved him no longer. Oh, the relief and the sense of liberation! It was strange to look back and remember how passionately she had yearned for him; she thought she would die when he failed her; she thought life thenceforward had nothing to offer but misery. And now already she was laughing. A worthless creature. What a fool she had made of herself! And now, considering him calmly, she wondered what on earth she had seen in him. It was lucky that Waddington knew nothing, she could never have endured his malicious eyeing and his ironical innuendoes. She was free, free at last, free! She could hardly prevent herself from laughing aloud.