Start with forgiveness.

     Learn to forgive. Let go of all the anger and hatred inside of you, if not because of the sake of letting the other person off then do it for your own good. By holding on to grudges and malice you might no realize it but you are preventing yourself form moving on. You might have succeeded in pushing the incident that caused it to the back of your mind but you won't be truly free until you learn to just let go and forgive. Now I know that it isn't easy to forget certain things depending on the magnitude of hurt it caused you but in order for you to proceed with the healing process you would have to learn to just forgive and only then will you get to slowly forget.

But first of all Start with forgiveness...

    If you are willing to forget about what has happened to you but still lack a way to move forward and put it behind you. Then this is the way to go, forgive the person that hurt you and most importantly forgive yourself. Even if you are the offender and you feel deeply remorseful for what you put your friend through, you have begged but still cannot forget what happened in between you both, then I tell you now to first of all ask for forgiveness and when it is granted, then it is time for you to forgive yourself to move past it. That is the only way you will be able to leave what has happened in the past and move forward.
      When I discussed this amongst friends, they reminded me of how no matter how hard you try certain things just stick to your memory and refuse to go away. And I say that I understand how that happens but I would also tell you that those flashes of bad times in your memory would only stay as scars and no more open wounds if you start working on your forgiveness, they would only serve as a reminder of the things you have gone through and help in building you to be wiser tomorrow.
 

   I admit that I don't know the kind of pain that some of you might have gone through, I don't know the kind of hurt or betrayal that trusted ones must have caused you. But what I know is that you won't be able to recover from all that if you still hang on to all that has happened. I just ask that you listen to me and learn to let go. I am talking to you that has a heavy heart from that heartbreak from your lover, you that has suffered betrayal from a trusted friend, you that was surprised by the backstabbing act of a loyal counterpart. Let go and I promise you, you will feel a lot better and your heart would seem lighter. Life is too short to hold on to all the hurt and pain...

Talk to a friend or talk to me, let me see a way I can help you get over the sadness. Betrayal is not an easy thing to handle and it would be best if you don't handle it alone. It will take time but with the right attitude and right friend, you will surely get over this.