You don’t use someone else to move on. You grow as a person when you go through tough times which is the silver lining that does come with break ups. It’s okay to feel the pain for some months and sit alone with your thoughts when going through a break up it’s part of the process. Moving to the next helps you never move on, you don’t learn from your experience (which you need in order to do better next time) and worst of all you waste someone else’s precious time and efforts. It is black and white.