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.
This is how I feel about graduating college and leaving all of the amazing friends I have made over the past 4 years! You all made saying good-bye so hard and I love you for it. Thank you for being part of my life!