A. The plaintiff and C are legally married couple around October 1994, and have two adult children among them.

B. The Plaintiff, C, and the Defendant came to know while receiving a swimming course in the same swimming pool, and became aware of the fact that they were friendly while carrying out the same kind of friendship and leisure activities.

C. From December 2016, the Defendant committed an unlawful act, such as adultery, while maintaining a friendly relationship with C. D.

Around September 21, 2018, when the Defendant and C’s illegal relationship were discovered to the Plaintiff, the Defendant, on September 25, 2018, prepared and delivered to the Plaintiff a letter stating that “I will not communicate or meet with C.”

E. On October 10, 2018, the Plaintiff filed the instant lawsuit.

[Reasons for Recognition] Unsatisfy, each entry in Gap evidence 1 to 5 (including each number in the case of additional number), and the purport of the whole pleadings

2. Determination as to the cause of action

A. The act that a third party who is liable for damages causes mental distress to the spouse by infringing on or interfering with the common life of the married couple falling under the essence of marriage and infringing on the rights of the spouse as the spouse by committing an unlawful act with the spouse of the married couple constitutes a tort in principle.

(See Supreme Court en banc Decision 2011Meu2997 Decided November 20, 2014). Also, tort liability borne by either spouse and a third party is jointly and severally liable as a joint tort.

(Supreme Court Decision 2013Meu2441 Decided May 29, 2015). The fact that the Defendant knowingly committed an illegal act with C with C despite being aware of his/her spouse’s existence is as seen earlier. Such an act by the Defendant is reasonable to deem that the Plaintiff infringed upon the rights of the Plaintiff’s spouse as C, and it is clear in light of the empirical rule that the Plaintiff suffered a serious mental pain.

Therefore, the defendant, as the joint tortfeasor, has the obligation to compensate the plaintiff for the above mental damage.

(b).