I think I get what you're saying, but please let me know if I'm wrong which is very possible. But to me, it sounds as if you feel very guilt about something to do with the way that relationship ended. Fantasizing about a second chance or hoping to run into them as almost a new person makes me feel like something's making you feel like the person you are now ruined everything.

If this guilt is really there, it may be vital to find ways to express and resolve that guilt. Not to that person, as you may have been seeking, but to yourself. Forgiving yourself may be difficult, but can also do wonders. Life changes, some relationships fall apart, but there's no way to go into the past and make a new outcome. Yet, if you forgive yourself in the now, then you'll find the strength to let go of a desired outcome, and more importantly find the strength to seek new, unknown, and mysterious outcomes with other people instead.

However, if I'm wrong then most of this won't apply, so just disregard it.