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.
breakups hurt, but losing someone who doesn't respect and appreciate you is actually a gain, not a loss. (this goes for friendship breakups, too.I know this, just had to "breakup" with a so-called friend)