The person might not be who you thought they were; might have changed for the worse; but in the memories, they will always be the person you loved. it's ok to cherish those memories. You dont have to allow that person in your life now.
Sometimes they just don't get that after you let the wounds heal, that that part of you is stronger than before,.and though you are kind, you will not allow them to hurt you anymore. When you realize you're worth it.