In order to let that pain go, in order to remove this person from the place of power they have occupied for so long, YOU MUST LET EVERYTHING GO.
Perhaps in a very distant future, you will be able to pick and choose the memories you want to keep, but for a very long time, one memory will always bleed into another. You CANNOT simply think about the time the two of you sat on the beach for an entire night, talking about your childhood, drinking the second-least-expensive pre-made cocktail drink you could find in the store. Because when you allow yourself to think about that, it will remind you of them as a whole, and will lead into all of the terrible things that happened after that night – not the least of which being their eventual departure. They exist within us as whole people, stories with beginnings and endings, and in order to let go of them we cannot choose the things we want to isolate for nostalgia.
We have to stop caring what they would think if they saw us, stop worrying about running into them in the store, stop obsessing over the things we could have done differently to make them stay. And that means letting go of everything they meant to us, proving to ourselves that life can be just as good, just as beautiful, without them in it. When you realize, long after the fact, that you no longer care about someone – that what they are doing in life has no bearing on you, and vice-versa – it feels very much like a small death. Who they were with you no longer exists, and you cannot even preserve it in your memory, for the sake of your own mental health.
You stop allowing their history to have any meaning for you today. You let them change their haircut, let them move, let them fall in love again. And when you see this person you have let go, you realize that there is no reason to be sad. The person you knew exists somewhere, but you are separated by too much time to reach them again.
Life should not end where heartache begins.