Step one:
The first thing that you need to do in order to truly forgive somebody is to acknowledge the fact that you have been hurt. For some people this can be the hardest part of forgiving somebody because we cannot admit that we have been hurt, we can't admit it to other people, let alone ourselves. Since the pain is already there what we need to do is acknowledge who, what, and how you have been hurt to begin the forgiveness process. You cannot move on to the next step or with your life until you have managed to complete this step.

Step two:
You are going to need to be the bigger person when it comes to forgiving somebody. You cannot wait for them to come to you and apologize, instead you need to approach them and apologize first. However, when you do apologize do not do it just to be the person who says it first, only say it because you really mean it. Many times people hurt you because they have been hurt as well, so you cannot expect somebody who is feeling hurt by something that you did to come and apologize first. You need to go to them and be the bigger person.

Step three:
You are going to need to be patient because it can take a lot of time for that pain to go away. You cannot expect the pain to go away the moment that you acknowledge that you have been hurt and tell the person that you forgive them. In some cases, you might need to seek counseling to help deal with the feelings of anger and resentment that have built up from your being hurt. Counseling can help you to understand why you got so hurt over this incident and why several months or years later you are still feeling the hurt.

Step four:
Before you can begin to let this person back into your life you are going to need to forgive yourself. Forgiving yourself is going to be even harder than acknowledging the fact that you have been hurt because you are going to have to be very honest with yourself. You are going to need to admit to yourself the role that you played in why you were hurt, but you also cannot justify your behavior. You have to come to terms with the fact that you contributed to your own feelings of hurt. In doing this you need to understand that, what you did was wrong, but that does not mean that you are a bad person.

Step five:
When forgiving somebody it is very hard to let that person back into your life is hard. What you need to do when letting that person back into your life is to set limits. You want to have that person promise that they will not hurt you again and if they truly commit to not hurting you then let them back fully into your life. You will want to start small when setting the limits to see if they are truly committed to not hurting you.