A. The Plaintiff and C are legally married couple on February 10, 2010 and have two children under their chains.

B. Around November 2013, the Defendant came to know that C was a part-time student of a store operated by C, and maintained an inappropriate relationship, such as having a sexual relationship, even though C was aware that it was married from May 2014.

[Grounds for recognition] The items of evidence Nos. 1, 2, and 7 of evidence Nos. 1, 2, and 7, and the purport of the whole pleadings

2. Determination:

A. A third party who has a liability for damages shall not interfere with a marital life falling under the essence of marriage by intervening in a marital life of another person and causing a failure of the marital life. The third party's act of infringing on the marital life falling under the essence of marriage by committing an unlawful act with one of the married couple, or interfering with the maintenance thereof, and infringing on the spouse's right as the spouse, thereby causing mental pain to the spouse, in principle, constitutes tort.

(See Supreme Court Decision 2004Da1899 Decided May 13, 2005, etc.). According to the above facts, the defendant, despite being aware that C is a spouse, maintained an inappropriate relationship for a considerable period of time with the knowledge that C is a spouse, and thereby, the plaintiff's marital life was infringed or interfered with the maintenance thereof. Thus, the defendant has a duty to pay mental suffering suffered by the plaintiff in money.

B. Furthermore, the scope of the Defendant’s liability for damages and the following circumstances revealed by the purport of the entire pleadings, along with the above recognized facts. In other words, the Defendant was a minor at the time of commencing an unlawful relationship with C, and the Plaintiff did not take any legal measures, such as filing a claim for divorce with C, and only one of the unlawful acts is liable, and the Plaintiff and C’s marriage period and family relationship, and the Defendant and C’s unlawful act.