(a) A third party who has a liability for damages shall not interfere with a married couple's community life falling under the nature of marriage, such as interfering with a couple's community life by interfering with another person's community life;

In principle, a third party's act of infringing on or interfering with a marital life falling under the essence of marriage by committing an unlawful act with either side of the married couple and causing mental pain to the spouse by infringing on the rights of the spouse as the spouse.

(See Supreme Court en banc Decision 201Meu2997 Decided November 20, 2014 (see, e.g., Supreme Court en banc Decision 201Meu2997). “Unlawful act committed by a spouse” under Article 840 Subparag. 1 of the Civil Act is a wider concept including a adultery, and does not reach the common sense, but includes any unlawful act that does not faithfully fulfill the marital duty (see, e.g., Supreme Court Decisions 88Meu7, May 24, 198; 2010Meu4095, Nov. 28, 2013). Whether an act constitutes an unlawful act ought to be evaluated in consideration of the degree and circumstances depending on each specific case.

(See Supreme Court Decision 92Meu68 Decided November 10, 1992, etc.; Supreme Court Decision 2010Meu4095 Decided November 28, 2013, etc.). In full view of the following: (a) Evidence Nos. 1 through 9-2; and (b) evidence Nos. 13-1 through 16; and (c) the overall purport of oral argument, including the following: (a) the Plaintiff and two children (the birth date 196, 1998, 198, 200, 3) were born and brought up on a marriage on August 4, 1995 and maintained their common life; (b) the Defendant was aware that his spouse had been a spouse; and (c) the Defendant was detrimental to the Plaintiff’s communal living or infringed upon the Defendant’s unlawful act; and thus, (c) the Defendant was found to have committed an unlawful act.