It's rude to cheat on your partner.
Jessica is approached by a coworker named Stuart, who asks her on a date despite knowing that Jessica has a boyfriend.
Jessica wants to respond to the invite.
Jessica turns down the invitation and says that she wants to stay loyal to her boyfriend.
Jessica agrees to the date which leads to her having an affair with Stuart.
Her boyfriend later finds out about the situation, and his trust for Jessica grows deeper.
Her boyfriend finds out about the affair and breaks up with Jessica for being unfaithful.