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.
I thought about you today and I didn't want you. Thinking about you doesn't make me happy anymore. It does excite me. I don't feel the need to hear your voice anymore or see your face ever again. (I Want A Divorce)