The Titan by Theodore Dreiser — Read

The result of this understanding was not so important to Cowperwood as it was to Antoinette. In a vagrant mood he had unlocked a spirit here which was fiery, passionate, but in his case hopelessly worshipful. However much she might be grieved by him, Antoinette, as he subsequently learned, would never sin against his personal welfare. Yet she was unwittingly the means of first opening the flood-gates of suspicion on Aileen, thereby establishing in the latter's mind the fact of Cowperwood's persistent unfaithfulness.

The incidents which led up to this were comparatively trivial--nothing more, indeed, at first than the sight of Miss Nowak and Cowperwood talking intimately in his office one afternoon when the others had gone and the fact that she appeared to be a little bit disturbed by Aileen's arrival. Later came the discovery--though of this Aileen could not be absolutely sure--of Cowperwood and Antoinette in a closed carriage one stormy November afternoon in State Street when he was supposed to be out of the city. She was coming out of Merrill's store at the time, and just happened to glance at the passing vehicle, which was running near the curb. Aileen, although uncertain, was greatly shocked. Could it be possible that he had not left town? She journeyed to his office on the pretext of taking old Laughlin's dog, Jennie, a pretty collar she had found; actually to find if Antoinette were away at the same time. Could it be possible, she kept asking herself, that Cowperwood had become interested in his own stenographer? The fact that the office assumed that he was out of town and that Antoinette was not there gave her pause. Laughlin quite innocently informed her that he thought Miss Nowak had gone to one of the libraries to make up certain reports. It left her in doubt.