1. The plaintiff's appeal and the defendant's incidental appeal are all dismissed.

2. Costs arising from an appeal and an incidental appeal shall be respectively.

1. Facts of recognition;

A. The Plaintiff is a legal spouse of C, and has a child of one male and female between C and C.

B. Around December 2014, the Defendant first known C while boarding a taxi driven by C, and had sexual intercourse with C while drinking alcohol on February 2015, and developed the horses of Germany into one’s reliance relationship.

C. Since March 2015, even though the Defendant became aware of the fact that C had a legal spouse, C had been living together with C at the Defendant’s home after April 2015, and maintained C and C by December 2015.

[Recognition] Facts without dispute, Gap evidence 4-1, Gap evidence 6, 7, and 11-1, and the purport of the whole pleadings

2. Determination

A. 1) 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 spouse’s right as the spouse by committing an unlawful act with the spouse, thereby constituting tort (see, e.g., Supreme Court Decisions 2013Meu2441, May 29, 2015; 2004Da1899, May 13, 2005). The tort liability owed by either of the married couple and the third party is jointly and severally liable as joint tort (see, e.g., Supreme Court Decision 2013Meu2441, May 29, 2015). According to the above recognition, the Defendant maintained an inappropriate relationship by living together with C after becoming aware that the spouse is a spouse, and the Defendant constitutes an unlawful act that infringes on the spouse’s right as a result of the Plaintiff’s communal living or his/her mental impairment.