Without evidence of an affair, can I not proceed with a lawsuit against the adulterous partner (female)?

A lawsuit for damages against an affair partner under Article 750 of the Civil Act and other provisions (a so-called 'lawsuit against the adulterous partner (female)') cannot be brought on the basis of mere suspicion or circumstances alone; it is established only where it is proven that infidelity between the spouse and a third party actually existed.

In other words, where legally effective 'evidence of an affair' does not exist, even if you file a lawsuit, it is difficult for the plaintiff's claim to be granted.

The key elements that a court examines in such a lawsuit are the following three.

① Whether the adulterous partner (female) was aware that the other party's spouse was married

② Whether, despite this, infidelity continued between the two

③ Whether the plaintiff suffered mental distress due to that infidelity

The evidence that an ordinary person can collect to prove these three is diverse.

For example, if text messages or messenger conversations contain expressions of affection or circumstances of secret meetings, they can be very powerful evidence.

In addition, photos of entering or leaving a motel, vehicle black box footage, and location records can also be used as circumstantial evidence supporting infidelity.

As for mental distress, it can be proven with a diagnosis of depression, counseling-center records, statements from family members or acquaintances, and the like.

In particular, the fact that the adulterous partner (female) was aware that the other party was a married man is an essential requirement for recognizing tort liability (see Supreme Court, Judgment 87Meu19).

If there is no material proving such awareness, the court may deny intent or negligence and dismiss the claim for damages.

Accordingly, a recording in which the married status is implied or mentioned in conversations with the other party, a statement from an acquaintance supporting that the married status was recognized, public documents, or circumstantial evidence become important materials for the court's judgment.

Ultimately, a lawsuit against the adulterous partner (female) brought without substantive evidence of infidelity may have considerable legal limitations, so the thorough collection of evidence of an affair should come first before litigation.