You may not want to leave your memories in the past, but you need to. I never left anything in the past. But that was also ruining my present and future. I know that it wasn't the right thing to do, but I kept doing it. I kept bring the past up to not just one person but everybody. It wasn't fair to them or even to myself.
Now let me rephrase all of this one-by-one. The past is the past — leave it there. It may not be exactly what you want to do, but it is what you need to do to move forward. Trust me on that one. I was the type of person who brought everything back up, and it was ruining everything for me and for my future with anyone. I understand if you are hurt by something in the past, but it's the past for a reason. Live your life to the fullest. Look forward to everything coming up and love yourself. Don't keep looking back at the things that don't matter anymore.
Memories are memories for a reason — don't ever forget that. You can have memories with anyone, your friends or people you aren't friends with anymore. You will always be able to cherish them. But you also need to remember, you can't relive them. People change everyday and it doesn't matter what you try to do to stop it. People will always change.
However, people don't always change for the better, some do change for the worse. Whether you like it or not, you will need to accept it. It's not a bad thing to leave the past in the past. I finally learned to do it and I'm much happier with my life. Everyone needs to try to do it. Just keep telling yourself, it's the past for a reason. Leave it there. Here I'll say it one last time — leave the past in the past. Do it for not only you but everyone else in your life or who was in your life at one point.
You may not be okay with it being in the past, but it will help your future grow. Don't you want that? You want your future bright. So look at it like this, you are forgetting the past for you, you are moving on for you, you are doing all of this for you. So keep moving forward and realizing you are better off with all of those things in the past and that they are only memories now. Never forget why you are where you are at this point in time. If it wasn't for the past happening, you wouldn't be so successful and happy with life. You may not be happy with everything that happened, but love the life you are living. Because one day you will be in someones past and they will try to move on from that like you are moving on. Do this for you and only you. No one else.