We are learning from Case Studies in Business Ethics by the late Rabbi Dr. Aaron Levine z"l professor of economics at Yeshiva University.
We have already established that lying to maintain domestic harmony is sometimes permitted. However, the Gemara in Yevamot on 63a seems to contradict this.
The Gemara tells a story about the wife of Rav who spitefully tormented him. "If he asked her to prepare lentils she would prepares peas. If he asked for peas she would prepare lentils." When his son Hiyya grew up he gave her his father's instructions in reverse. "Your mother," remarked Rav to him, "has improved." At that point Hiyya revealed to his father that it was in fact he who had made her seem to improve by reversing the orders. Upon hearing this Rav admonished his son and requested that he stop engaging in falsehood, even for the sake of harmony.
Why was lying not permitted in this case if it helped to bring domestic harmony?
Rav Solomon Luria (Poland, 1510-1573) noted this seeming contradiction. His answer was that the difference between this case and other cases that we mentioned is that this was a habitual lie. To be successful Hiyya had to engage in this ruse for an indefinite period of time which would inevitably have a negative effect on his character.
R. Nahum Yavrov (Israel, contemporary) posits that any falsehood, even for the sake of domestic harmony, must not be used in the presence of children. According to him moral education of children is, in some instances, even more important than domestic harmony.