1. Of the judgment of the court of first instance, the part against the defendant in excess of the following amount ordered to be paid shall be revoked.

1. The parties' assertion

A. The plaintiff is a married couple with the non-party C, and there is two children between them.

From January 2017, the Defendant entered into an inappropriate relationship with C, and accordingly, the relationship between the Plaintiff and C has reached a failure to the extent that it is impossible to recover.

The defendant shall pay consolation money of KRW 30 million and delay damages to the plaintiff.

B. The Defendant did not have any improper relationship with the Defendant C, and the marriage between the Plaintiff and C was a de facto failure on or around November 2016 due to the Plaintiff’s economic uncertainty, etc.

2. Determination

A. 1) The husband and wife bears the duty of good faith to not engage in any unlawful act. The term “unlawful act” includes any and all unlawful acts that are not faithful to the husband and wife’s duty of good faith even if they do not reach the marital relationship. If one spouse commits an unlawful act, the husband and wife is liable to compensate for mental distress inflicted upon the spouse (see, e.g., Supreme Court Decisions 87Meu5, 87Meu6, May 26, 1987; 87Meu6, May 26, 1987). Meanwhile, the third party shall not interfere with the common life of the husband and wife falling under the essence of marriage, such as intervention in the other spouse’s common life. The third party’s act of infringing on the husband and wife’s marital nature or interfering with their maintenance and the spouse’s rights as his spouse, and the act of infringing on the spouse’s rights as his/her spouse, in principle, constitutes a tort (see, e.g., Supreme Court Decisions 2013Meu241, May 29, 2019.