Can you make a claim against an affair partner if your marriage was never registered?

More couples than you might think have held a wedding ceremony but put off registering their marriage for one reason or another. Then, on discovering a spouse's affair, they hesitate, wondering whether they have no rights because they never registered. The law does not see it that way. If you intended to marry and actually lived as a married couple, you are protected as being in a de facto marriage (사실혼), and you can also hold the affair partner who infringed that relationship responsible.

The starting point is proving it was a de facto marriage

A de facto marriage is recognized only when there is both an intention to marry and the substance of married life together. It is not decided by the length of cohabitation alone; the court looks at whether people around you treated you as a married couple and whether you ran your life together. If it is assessed as cohabitation while dating, it is difficult to claim consolation money from either the partner or the affair partner.

So in de facto marriage cases, materials showing the substance of the relationship are as important as evidence of the infidelity. What a single marriage relationship certificate would settle in a legal marriage has to be filled in with a variety of materials.

• Wedding photos, wedding invitations, records of the families' formal meeting
• Records of attending holidays and family events on both sides together
• Account records showing living expenses or loans were shared
• Hospital or school documents listing you as spouse or guardian
• Move-in records at the same address, lease agreements

Even if there were periods when you lived apart for work, that does not immediately rule it out. If you held a wedding, attended family events together and lived as a married couple, a de facto marriage may be recognized, so prepare materials showing why you lived apart and how often you saw each other.

The affair partner must have known of the relationship

Because the marriage was not registered, affair partners often argue that they didn't know the two were married. You need materials showing that the affair partner knew the two lived together or had held a wedding. Records of the spouse calling you ‘my wife’ or ‘my husband’ in conversations with the affair partner, records of meetings near the home you shared, and wedding photos posted on social media are used. If the affair partner attended the wedding as a guest, or socialized with the two of you as a couple in the same group, that alone is strong evidence. Conversely, if you did not tell people around you about the marriage, it is that much harder to show what the affair partner knew.

Some de facto marriages are not protected

A de facto marriage with someone who has a legal spouse is, absent special circumstances, not given protection equivalent to a legal marriage. According to case law, the same applies even if the legal spouse had left home long ago (Supreme Court judgment 96Meu530 of September 20, 1996). Conversely, if you are the legal spouse and your spouse is living with someone else as if in a de facto marriage, that person can be held responsible as an affair partner.

A de facto marriage can be ended without any filing, so when an affair comes to light, the end of the relationship, consolation money and property issues are often disputed all at once. A claim for consolation money must be made within 3 years of learning of the harm and the person responsible (Article 766 of the Civil Act), so keep a record of the dates the relationship ended and you learned of the affair. Around this time, you should also decide whether to pursue the claim against your de facto spouse or the claim against the affair partner first, or both together.