Divorce & Infidelity

Third-Party Adultery Lawsuit Defense Lawyer

Third-Party Adultery Lawsuit Defense Lawyer | Building a Defense When You Are the One Being Sued

Summary

A "sang-gan-nam/sang-gan-yeo" lawsuit is a civil tort claim brought by the betrayed spouse against the third party who is alleged to have had a sexual relationship with their spouse, seeking money damages for infringement of the marital relationship (민법 제750조). Being named as a defendant does not mean liability is settled — the plaintiff must prove both that a sexual relationship occurred and that you knew, or should have known, the other person was married. Even where some liability is found, the amount of compensation varies enormously depending on the length and intensity of the relationship, the state of the marriage before you were involved, and whether you actively pursued the relationship or were misled about the other person's marital status.

Civil Litigation Related law: Civil Act (민법) Defendant / Third-Party Perspective Damages Reduction

Third-Party Adultery Lawsuit Defense | How Courts Decide Whether You Are Liable at All

Liability is not automatic just because a relationship existed. Korean courts require the plaintiff to prove two separate things, and a defense often succeeds by attacking either one.

Proof of an actual sexual relationship

The plaintiff must prove there was an actual sexual relationship, not merely a close friendship, frequent contact, or emotional intimacy (대법원 판례상 확립된 기준). Text messages, photos, or hotel records are often submitted as evidence, but their weight depends heavily on context — ambiguous messages alone rarely meet this bar.

Knowledge that the person was married

Liability generally requires that you knew, or negligently failed to find out, that the person was married (민법 제750조에 따른 고의·과실 요건). If the other party actively concealed their marital status — for example, claiming to be divorced or separated, or hiding a wedding ring and using a different address — this can be a real basis to argue you acted without fault.

Marriage already broken down before your involvement

Korean courts have held that no tort liability arises if the marriage had already substantially broken down before the third party became involved, since there is no longer a marital relationship left to infringe (대법원 판례). Evidence of prior separation, existing divorce proceedings, or long-term estrangement between the spouses is central to this defense.

Third-Party Adultery Lawsuit Defense | Strategies to Reduce or Eliminate the Damages Amount

Even when some fault is acknowledged, the amount awarded is highly fact-specific. Courts weigh a wide range of mitigating factors, and a well-prepared defense presents these systematically rather than simply denying everything.

Duration and intensity of the relationship

A brief, isolated encounter typically results in a lower award than a prolonged, ongoing relationship. Documenting the actual timeline — rather than letting the plaintiff's characterization stand unchallenged — is one of the most effective ways to narrow the damages figure.

Who initiated and who was deceived

If you were led to believe the person was single, separated, or already living apart from their spouse, this reduces the degree of fault attributed to you and can be argued as a mitigating factor even if some negligence remains. Conversely, evidence that you knew about the marriage from early on and continued the relationship works against reduction.

Comparative fault of the unfaithful spouse

Because the unfaithful spouse is typically a joint tortfeasor with the third party, disproportionate blame placed solely on you can sometimes be balanced by pointing to the spouse's independent responsibility, particularly where the marriage was already troubled for reasons unrelated to you.

Ongoing settlement or prior partial payment

Courts consider whether an apology, settlement offer, or partial payment has already been made in assessing the final amount and in framing the overall conduct of the defendant. Any prior communication with the plaintiff should be reviewed carefully before responding, since admissions made informally can later be used as evidence.

Third-Party Adultery Lawsuit Defense | From Receiving the Complaint to Resolution

Initial review of the complaint and evidence
We review the complaint, the plaintiff's evidence, and the procedural timeline (including the deadline to file your answer) to assess what is actually being alleged and what has and has not been proven.

Fact-finding and evidence gathering
We work with you to reconstruct the actual timeline of the relationship, identify any evidence of the marriage's status before your involvement, and gather materials supporting deception or lack of knowledge where relevant.

Filing the answer and defense strategy
We file a formal answer addressing liability and, where appropriate, argue in the alternative for a reduced damages amount, presenting mitigating facts even where full denial is not realistic.

Settlement discussion, if appropriate
In many cases a negotiated settlement produces a better outcome than continued litigation; we advise on realistic settlement ranges based on comparable case outcomes and the strength of your position.

Hearings and final judgment
If the case proceeds to judgment, we represent you at hearings and in written submissions until the court issues its decision on liability and damages.

Third-Party Adultery Lawsuit Defense | How Legal Fees Are Determined

Retainer fee (착수금)
Generally set based on the complexity of the factual dispute — whether liability itself is contested, or the case is limited to negotiating the damages amount — and the amount of damages claimed by the plaintiff.

Contingency component (성공보수)
May apply based on the difference between the amount claimed and the final amount awarded or settled, giving the firm a direct incentive to minimize your exposure.

Cost of evidence gathering
Where private investigation, digital forensics review, or expert document analysis is needed to establish the timeline or the marriage's prior status, these costs are estimated separately and discussed before they are incurred.

Court and filing costs
Statutory stamp duty and service costs are calculated based on the amount claimed in the complaint and are separate from attorney fees.

※ Costs vary depending on case complexity and specific circumstances; exact fees will be provided during consultation. No specific outcome is guaranteed.

Third-Party Adultery Lawsuit Defense | Self-Check Before You Respond

1️⃣ Before You Answer the Complaint

Have you confirmed the exact deadline to file your answer stated in the complaint?
Have you avoided sending any apology or admission message directly to the plaintiff?
Have you kept all messages, calls, and documents related to the relationship without deleting anything?
Do you know whether the other party's marriage was already troubled before you met them?

2️⃣ Assessing the Strength of the Evidence Against You

Does the plaintiff's evidence actually prove a sexual relationship, or only frequent contact?
Is there any objective evidence (messages, statements) showing you were told the person was single or separated?
Can you establish roughly when the relationship began and how long it lasted?
Is there evidence the marriage had already broken down independently of you?

3️⃣ Considering Settlement

Has the plaintiff proposed a specific settlement amount, and is it documented in writing?
Would settling now avoid a public record of a court judgment against you?
Have you compared the proposed amount against outcomes in factually similar cases?

Frequently Asked Questions

Q. I received a complaint saying I am being sued as the third party (sang-gan-nam). Does this mean I will definitely have to pay?

A. No. The plaintiff must still prove both that a sexual relationship occurred and that you knew or should have known the other person was married. Many cases end with no liability, reduced liability, or a settlement well below the amount originally claimed.

Q. What if I truly did not know the person was married?

A. Lack of knowledge, if it was not due to your own negligence, can be a full defense because liability under the Civil Act generally requires intent or negligence (민법 제750조). Evidence such as messages where the person denied being married, or specific efforts they made to conceal it, strengthens this argument.

Q. Can I still be liable if the marriage was already falling apart before I got involved?

A. Korean courts have found no tort liability where the marriage had already substantially broken down before the third party's involvement, because there was no longer an intact marital relationship to infringe. This requires concrete evidence of the prior breakdown, such as an existing separation or divorce filing.

Q. How is the damages amount actually calculated?

A. There is no fixed formula. Courts consider the duration and nature of the relationship, the degree of fault and deception involved, the impact on the marriage and any children, and the financial circumstances of the parties, weighing all of these together rather than applying a set multiplier.

Q. Should I respond to the plaintiff directly to try to resolve this quietly?

A. This is risky without legal advice, because informal messages — including apologies — can later be submitted as evidence of admission. It is generally safer to route any settlement discussion through counsel.

Q. What happens if I ignore the complaint and do nothing?

A. If you do not file an answer within the deadline, the court can enter a default judgment based largely on the plaintiff's version of events, which typically results in a worse outcome than if you had contested the claim.

Q. Can the unfaithful spouse also be sued, and does that help me?

A. Yes, the unfaithful spouse can also be named as a joint tortfeasor, and their independent share of responsibility can sometimes be used to argue that the damages attributed to you specifically should be lower.

Q. Is there a time limit for the plaintiff to file this kind of lawsuit?

A. General tort claims are subject to statutory limitation periods under the Civil Act, and a case filed long after the plaintiff learned of the relationship may be vulnerable to a limitation defense; the exact timing should be reviewed against the specific facts (민법상 소멸시효 규정).

Q. Will this lawsuit show up on my criminal record?

A. No. This is a civil damages claim, not a criminal proceeding, so a judgment against you results in a monetary obligation, not a criminal record.

Q. What evidence should I start gathering right now?

A. Preserve all communications with the other party and any documents relevant to how the relationship began and how long it lasted, and try to identify anything showing the state of the couple's marriage before you were involved — these are the two pillars most defense strategies are built on.