Organizing & Preserving Evidence of Infidelity

In affair cases, a single decisive photo is rare. The court puts chats, payment records, movement records and statements side by side to judge when the relationship began and how long it continued. So once the material is collected, we build one table in date order and check where the gaps are.

Material is sorted by three questions: Were the two in a romantic relationship? Did the affair partner know about the marriage? Were you and your spouse living together at the time? In actual consultations, evidence is often concentrated on the first question while the other two are left empty.

Recording a conversation you take part in is not a violation of the Protection of Communications Secrets Act (통신비밀보호법), even without the other person's consent. A recording made while discussing the affair with your spouse, or while on the phone with the affair partner, can be submitted as evidence. On the other hand, placing a recorder in your spouse's car or room to record the two of them is recording a conversation between other people: it is punishable and cannot be used in court.

Secretly installing a location-tracking app or GPS device, breaking into your spouse's account with their password, or entering the affair partner's home to film can also lead to problems under the Location Information Act (위치정보법), the Information and Communications Network Act (정보통신망법) or trespass laws. Unlawfully gathered material can also give the other side grounds to file a counter-complaint or to argue for reduced compensation.

• Acceptable: recordings of conversations and calls you took part in, screenshots of public social media, your own car's dashcam, material your spouse showed you voluntarily
• Avoid: secretly accessing your spouse's phone or accounts, recording conversations between other people, installing tracking devices, entering the other person's home

CCTV at lodging businesses or buildings is often overwritten after a certain period, and businesses usually refuse to show footage, citing personal data. In that case, even before filing a lawsuit, you can apply to the court for evidence preservation (증거보전) and obtain a decision ordering the business to submit the footage to the court.

The application must state the other party, the facts to be proved, the evidence to be preserved and the reason for preservation, and you must make a prima facie showing of that reason (Civil Procedure Act (민사소송법) Article 377). The more narrowly you specify the place, date and time of the recording, the more likely the application will be granted. You can apply even without knowing the affair partner's name, but if the dates in the application don't match the dates in the material, the court will ask for corrections, so it must be accurate from the start.

Many people turn to private investigation agencies to gather evidence of an affair. Getting a report on what was observed in public places and following someone to track their location or secretly recording conversations are viewed completely differently under the law. If the agency uses unlawful methods, not only can the results not be used, but the client can also get into trouble.

Before hiring anyone, first check what the material you have now proves and what is missing. If the gaps can be filled through a court fact inquiry (사실조회) or evidence preservation, there may be no need to hire an investigator at all.

If you keep only screenshots and delete the original chat room, it becomes hard to respond when the other side claims they were edited or fabricated. Leave the chat room as it is, and save screenshots so the other person's name and the date appear together. Do not edit recordings; prepare the original file together with a transcript.

Also avoid telling the other side in advance that you have evidence. It gives the affair partner time to delete chats or get their story straight with your spouse.