The ideal ego is not to be confused with the ego-ideal, this is something that the psychologist can discover of his own accord… what still remains obscure, is the difference between the two series that Freud distinguishes
Lacan insists on the structural non-identity of the ideal ego and the ego-ideal, identifying their distinction as the central unresolved problem in Freudian identification theory.
, The Seminar of Jacques Lacan, Book VIII: Transference, 2015thesis