How many times in our lives have we asked ourselves "How could he/she do this to me? Does the question "How could he/she be so cold/cruel/callous?" Sound familiar?
It takes courage and strength to journey back to that place in time and recognize the actual circumstances of the situation at that time. Experience teaches wisdom, and so a personal recommendation would be to take that journey as soon as possible, but only when one can put aside the emotional hurt that may cloud the actual facts.
The question one must ask and literally write the answer to is "What really happened?" The recommendation to committing the answer to paper is critical to this process. Tossing the answers around in one's brain, and critiquing them constantly is going to do more damage than good. This is a method that could prove to be unending, emotionally disturbing, and may prevent proper focus on the many other tasks that are required of us as we live our lives. If one has ever asked the questions that were in the opening paragraph of this writing, then it is fair to say that one has already agonized too much about an incident that one had no control over.
The main objective here is to focus entirely on the task at hand, and spend nothing short of the required time necessary to complete the task. This written statement of the facts must be edited and re-edited until the paper bears the facts and only the facts, as well as the truth and only the truth. One may find it necessary to take breaks of days or weeks between the editing and revision of each draft, but it is important that this writing is reviewed and edited until it is completely ensured that this is an entirely factual document that is completely devoid of emotion, lies, speculations, explanations, and assumptions. It is absolutely necessary that an exact and accurate description of what actually occurred has been composed and completed.
The incident itself, and the time frame over which the incident occurred are both irrelevant factors. Your question asked "How could he/she do this to me?" could have been a reaction to a spurned invitation to dinner, or it could be a reaction to a bitter divorce from a five year marriage, or a twenty-five year marriage. The incident itself does not matter. The hurt you experienced and perhaps still do experience is what matters. Your documentation of the facts has no required length. The only requirement is that all of the facts that occurred and only the facts that occurred are documented. A three paragraph paper on a twenty five year marriage that ended in divorce is no less detailed or important as a twenty page document on a three day weekend that you thought was the beginning of the living life happily ever after with the man of your dreams, and instead was a non-committal but fun and enjoyable weekend spent together by two people. Again, the only requirement for this document is that it contains only the facts. If she picked you up at 5:17 pm instead of 4:30pm and you wish to include this in your document that is fine. Any speculation on the reason for the delay, or speculation on what this delay should have demonstrated to you is taboo and must be deleted for the reason that only the actual facts that occurred are allowed in this document.
At this time, we are now free of the need or desire to speculate on what happened or what could have happened. Remember, we took a journey back to this time. It has already happened and nothing can change what happened. Our emotions, our mistakes, our unfulfilled hopes and dreams, our hurt, and anything else that we generated out of this occurrence in our life will not change anything about what actually happened. Most importantly, we have eradicated all of our numerous perceptions of what happened, and we have a self documented factual document to refer to as to what actually happened. We have removed all the emotion, speculation, and attachment to the occurrence. This document now contains all we need to remember about the incident.