Arrowsmith by Sinclair Lewis

He had promised to see Madeline the next morning.

By any canon of respectable behavior he should have felt like a low dog; he assured himself that he must feel like a low dog; but he could not bring it off. He thought of Madeline's pathetic enthusiasms: her "Provencal pleasaunce" and the limp-leather volumes of poetry which she patted with fond fingertips; of the tie she had bought for him, and her pride in his hair when he brushed it like the patent-leather heroes in magazine illustrations. He mourned that he had sinned against loyalty. But his agitation broke against the solidity of his union with Leora. Her companionship released his soul. Even when, as advocate for Madeline, he pleaded that Leora was a trivial young woman who probably chewed gum in private and certainly was careless about her nails in public, her commonness was dear to the commonness that was in himself, valid as ambition or reverence, an earthy base to her gaiety as it was to his nervous scientific curiosity.