TH as X would destroy the painting

There is a painting in which a world exists, inhabited by people, animals, and other creatures. X, is its painter. It was created ten years ago, and the people within it have advanced to a modern level of civilisation. Recently, X, who is a young person realised that the painting is sustained by their life, and at this rate, X will die within the next decade. Destroying the painting would stop it from draining X's life force, but everything inside it could never be recreated.