A. The plaintiff and C are legally married couple who completed the marriage report on January 15, 1997.

B. Around July 2017, the Defendant started teaching system from June 2018, with C and the company bonus.

Since then, the defendant had been aware that C has a spouse, repeated with the sex relationship, etc.

C. On October 10, 2018, the Defendant continued to meet C with the Plaintiff until January 2019, even after the fact was discovered to the Plaintiff.

[Ground of recognition] Facts without dispute, entry of Gap evidence 1 to 3, purport of the whole pleadings

2. Determination

(a) The husband or wife of a liability for damages, as a community combining mentally and physically, shall have the duty to cooperate comprehensively between themselves in order to maintain marriage as a common life of both spouses, and shall have the right to such obligation;

As such, as the content of the marital or marital life maintenance obligation, the married couple bears the sexual duty that should not commit any unlawful act.

In addition, a third party shall not interfere with a married couple's communal living which is the essence of the marriage by participating in a marital life of another person and causing the failure of the marital community.

In principle, a third party's act of infringing on a couple's communal life falling under the essence of marriage or interfering with the maintenance thereof and infringing on the right as the spouse, thereby causing mental pain to the spouse shall constitute a tort.

In light of the above legal principles, as seen earlier, the Defendant committed unlawful act, such as joining C in a marital state with the Plaintiff, and the Defendant’s unlawful act as seen above is reasonable to deem that the Defendant interfered with the maintenance of marital life and infringed upon the rights of the spouse as a spouse against the Plaintiff.

Therefore, due to the defendant's and C's improper act, the plaintiff has a considerable mentality.