Dorothy is seeking counseling due to difficulties she is experiencing in her marriage. She expresses that her husband is constantly accusing her of being selfish and failing to follow-through with her responsibilities. Dorothy is frustrated and confused because she says that he is actually the one who is selfish and irresponsible. The psychologist explained to her that this is likely a defense mechanism he is using to protect his ego from unconscious conflicts. Which developmental theory best describes the approach that the psychologist is using in this situation