It can be a very liberating thing to let go of your past. All too often, we hold on to things for silly reasons. These things can be physical items, like things from your childhood, something less tangible, like a relationship, or an abstract concept, like emotional attachment.
Why do you need these reminders if you have moved on and become a different person? Shouldn't we be able to scrape the flotsam and jetsam from our lives and move on with purpose? Trash is collected regularly. Use this service. As for the more intangible things, why hold on to them? Because it is the "right" thing to do? The only right thing that you need to do is what is right by you. It doesn't matter if a failed relationship is in your past. Did you do your best to try and save it? Then that's all you could do.
Scrape them off. Who needs them? Move on with your life. Make money, raise a family, get famous, write a book. Do what you want to do. If the people around you are not the people you NEED around you, leave them behind. As we get older, we mature. Usually. When you move on in your life and you have the people there that can't keep up, leave them in the dust. You are not there to garner anyone's approval except your own. It all comes down to this question: Can you live with your decision?
That is not a question to be answered lightly. You can't just say "Oh, uh sure. I guess." It takes some thinking. Can you live with cutting all ties to people in your past? Do you need them to make you happy? Is it worth the effort and frustration to try and rekindle a romance or friendship that has long since dimmed? Or, is it better to let the fire go out, extinguished forever. People make these choices every day. Some are done for the right reasons, some for the wrong ones.
It takes a certain level of self awareness and intelligence to properly perform such an introspective task, and I seriously doubt that many people can be as brutally honest with themselves as they need to be. Most often, ego and self-righteousness get in the way. During a process that should be governed solely by logic, emotion takes over and leads to snap (and often bad) decisions.
So be it, right? That's the way the human race functions. A stubborn, selfish, self absorbed species that is driven by the need to be accepted and loved by everyone around them. When that does not happen, it is all too often (not surprisingly) the other persons fault. When, the more likely facts is, if people don't want to be around you, it's your fault. Not theirs.