forgive and forget

(idiomatic, intransitive) Absolve completely for a past wrongdoing; pardon with neither resentment nor a view to retribution.

Example: 1875, Wilkie Collins, The law and the lady, page 33:
  "We will go away in the yacht. Does it matter where we live, so long as we live for each other? Forgive and forget! Oh, Valeria, Valeria, forgive and forget!"
2002, Jack Womack, Going, Going, Gone, page 73:
  'Not long before he died, the old man disowned him. Then a year and a half ago mom forgave and forgot.'