At first it’s going to hurt. You’re going to be so tempted to run back to try to make things better, your indecisive, fickle mind will be turning, but as much as you don't believe in grudges, please understand that leaving certain people in the past does not mean you are no longer patient or resilient--it just means that you realized your worth.
You'll have days where you feel empowered, free and on top of the world. You might see a light at the end of the tunnel as you remember the things you cared about before your mind was clouded with the perspective of someone so prone to selective caring.
Perhaps other days you'll be brought to tears by something as small as a loss of words as you both looked away like strangers who accidentally made eye contact. The emptiness between the two of you lingering like the scent of the heavy, warm, air after a summer rain shower.
These events might hit you once, twice, or not at all. But eventually, the memories will live in a separate part of your mind, like a scrapbook that you can skim through on a rainy day-- and you'll wear a nostalgic smile because you'll see how far you came.