Here’s the problem: the article never says he had sex with her. It’s worded in a way to make you draw that conclusion, but they are weasel words.
True. If Cain came out and said that he brought her home, had her sleep on the couch, and sent her home, then I’d take him at his word. But based on the few bits of information, it sound much more likely that something consensual happened, which isn’t harassment, but isn’t honoring his marriage either..