Have you ever went to Celebrate Recovery or Alanon? I attend CR for codependency and about a year and a half ago did a 12 step study. This had me literally work through just these types of issues and taught me how to let them go. The thing is, YOU are the one hurting by carrying around all this resentment. It hurts you much more so than anyone else, as you are expressing.
I do understand, however I know there are differences between forgetting and forgiving.
God Bless!