Neither. I wouldnlt forget or forgive as I waved them goodbye, throwing their possessions out the door.
Perhaps forget. Depends on the situation if it were just a one time thing or not. Because, if they truly were sincerely sorry, and if it were obviously clear that they really loved you and made the effort to make it up to you and never do it again, then it'd probably be ok to forgive them... because people do make mistakes, and sometimes, even under horrible circumstances like that, it makes a couple grow stronger, with the experience of almost losing their love forever just because of a one time thing. Forgetting is a lot tougher though, no matter what you do, once that trust is broken, it'll take a lot of time and effort to heal that relationship even after forgiving that person.