You shouldn't get involved in a relationship with an ex.
Katie, who is single, is feeling particularly lonely and has been talking to her ex who cheated on her.
Katie wants to be with someone romantically.
Katie keeps her ex at a distance and finds someone new on a dating website.
Katie rekindles her feelings with her ex and dates him again.
The ex regrets what he did when he sees her with a new partner.
The ex gets the impression that his previous actions are forgiven.