In some 'business trip cheating sex stories', the person on the business trip might be feeling lonely and vulnerable. They could meet someone at a business event or a hotel bar who seems very charming and alluring. Without thinking about the consequences, they engage in inappropriate behavior. But again, this is a negative behavior pattern that goes against relationship values.
Cheating during a business trip is unethical. However, in fictional stories, a common scenario could be that a married person meets an old acquaintance on a business trip. Temptation strikes when they start reminiscing about the past and one thing leads to another. But this is just a fictional idea and not something to be advocated in real life.