Forgiveness is the way to release the past and change your life for the better. The reason is that if we only forgive the person, we risk being hurt by another person doing the same thing as or similar to what the first person did to us. It is the power of the issue that we need to break. It is a childish notion that healing doesn't hurt. Surgery is painful but a much better alternative than losing one's life by not having it.
Forgiveness initiates the grieving process where real healing takes place.
During this process a lot of emotions will get stirred up and painful memories relived. Depression, fear, and even rage may take over for a time. Allow them to come up, do there necessary work, and then they will leave. It is when we do not let our emotions do what they were designed to do that they hang around for awhile, popping up as unexpected guests, at the worst possible moments. We're not talking about having a pity party or sending forgiveness Spam to millions of people on the Internet.