Ashley Madison filed the suit last year after its newly launched Korean website was shut down by authorities who alleged it incited immorality.
At the time, adultery was illegal in South Korea.
The company denied the allegations in its statement of claim, describing itself as "a social networking website facilitating communication between like-minded adults."
A spokesman for the company says the website has now been restored following a February decision by the Constitutional Court of South Korea to strike down the more than 60-year-old statute.
The CEO of Ashley Madison's parent company Avid Life Media says the website's presence in South Korea — and its challenge of the ban — helped speed up changes to the legal landscape there.
Noel Biderman says he believes the data Ashley Madison collects on adultery will help "change society's perception about non-monogamous behaviour" around the world.
"Not that long ago, a Canadian woman had an affair...we would call her an unfit mother and take away custody of her children, we would punish her in an alimony sense," he said.
That has changed over the years, and now "that recognition is going to spread further and further across the globe."
Another of the company's legal battles recently came to an end when the Ontario Superior Court dismissed a lawsuit filed by a former employee who claimed she was injured typing up fake profiles of sexy women to entice men to join the site.
Both the lawsuit filed by Doriana Silva and the countersuit by Ashley Madison were dismissed without costs.