How do you explain to a blonde that a coworker has a wife at home and is a good family man? She just doesn't get it! It is easier to cum in her mouth than to explain it. So his conscience can be calm - he did not cheat, he just bought the girl a cocktail. And he put it in her pussy just to make conversation - fuck me, das ist fantastisch. Let the blonde think it was her charm that worked and make her feel happy.
The guy was in the right place at the right time, the slender blonde was in the hunt and gladly took a cock buddy.