The ego is a concept Freud dreamed up without any empirical evidence to support his assertions about the way the mind supposedly works. What he was really doing was reusing aspects of the Christian mythology, probably without realizing it, in a way that appealed to his upper-middle-class Viennese Christian clients. His tripartite structure of ego, id, and super-ego has no evolutionary validity and no empirical evidence has ever been presented in support. We humans like simple myths, which is why religions have been with us for so long, but myths are rarely good guides to reality. Consequently I’d advise caution with regard to attempting to develop any “theory of living” based on a mythological structure of any kind.