You can’t change the past, but the past changes the present.
Something that happened in the past that you didn’t understand or couldn’t see the meaning becomes more clear as the present unfolds.
“We must abandon completely the notion of blaming the past for any kind of situation we’re in and reverse our thinking and see that the past always flows back from the present. That now is the creative point of life. So you see, it’s like the idea of forgiving somebody. You change the meaning of the past by doing that …” – Alan Watts, Out of Your Mind, from Reflections from Holstee newsletter
Even things that were horrible in the past take on new meaning if you grow and learn from them in the present.
That person that did the unforgivable must be forgiven for the present to take the shape that you want.
“Holding on to anger is like drinking poison and expecting the other person to die” – Buddha
The past does inform the present. That is why we need to be present in each moment. The present becomes the past.
Since we can’t change the past the only influence we have is being present in each moment.