Soldiers' Pay by William Faulkner

Emmy had become an obsession with Januarius Jones, such an obsession that it had got completely out of the realm of sex into that of mathematics, like a paranoia. He manufactured chances to see her, only to be repulsed; he lay in wait for her like a highwayman, he begged, he threatened, he tried physical strength, and he was repulsed. It had got to where, had she acceded suddenly, he would have been completely reft of one of his motivating impulses, of his elemental impulse to live: he might have died. Yet he knew that if he didn't get her soon he would become crazy, an imbecile.

After a time it assumed the magic of numbers. He had failed twice: this time success must be his or the whole cosmic scheme would crumble, hurling him, screaming, into blackness, where no blackness was, death where death was not. Januarius Jones, by nature and inclination a Turk, was also becoming an oriental. He felt that his number must come: the fact that it would not was making an idiot of him.