The vocation of each writer is to describe the world as he or she sees it; anything more than that is advertising.
If you never left anything or anyone there would be no room for the new. Naturally, to move on is an infidelity -- to others, to the past, to old notions of oneself. Perhaps every day should contain at least one essential infidelity or necessary betrayal. It would be an optimistic, hopeful act, guaranteeing belief in the future -- a declaration that things can be not only different but better.