That simply means that you never mattered in their life to begin with and they were just using you. But when they walk by your child that they told you they loved that's when you know there a cruel heartless bitch
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.