Love Lock Bridge, Paris---I was just there! and what a stunning view from the bridge! The lock idea is really interesting too, and the story that goes with them :) Even if it's not good for the bridge.
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.