Reconciling that which can never be repeated, except in the mind's eye, where it is broken and cannot be fixed. The suffering stems from this fact, from your inability to change what you perceive as the mistakes of your past.
You must surrender this pain to eternity, you must realize that the Universe only knows second chances, and you must understand that your only source of redemption is NOW. There is no redemption to be found in the repetition of past events within your mind, only more suffering.
The only redemption that exists is in the fluid and non-resistant action that can only occur NOW. You will find appreciation for your past mistakes and in this appreciation lies true healing.
Every mistake we make is like the space that exists between each step on a staircase. This space is what provides the platform for upward movement and growth. Without this space, there is no staircase, but only a ramp that you keep sliding back down. Trying to avoid mistakes out of fear of failure is the only true failure that exists.
Remember that your mistakes stemmed within you the will to change, and the sweetness of your success is always directly proportional to the depth and pain of your past transgressions.
"Forgiveness is the fragrance that the violet sheds on the heal that has crushed it." - Mark Twain