The Lady with the Dog
How we cite our quotes:
He was under forty, but he had a daughter already twelve years old, and two sons at school. He had been married young, when he was a student in his second year, and by now his wife seemed half as old again as he. (1.4)
This passage suggests that Gurov's reason for pursuing Anna has something to do with his fear of growing old.
But at every fresh meeting with an interesting woman this experience seemed to slip out of his memory, and he was eager for life, and everything seemed simple and amusing. (1.6)
A large part of the reason for Gurov's seducing Anna has to do with dissatisfaction with his own life.
Her expression, her gait, her dress, and the way she did her hair told him that she was a lady, that she was married, that she was in Yalta for the first time and alone, and that she was dull there... (1.7)
It's interesting that Gurov immediately characterizes Anna as bored, since this is actually his own boredom is actually the reason he pursues an affair.