Anyway DY's side refuted his allegations, and said they were married in 2018 before divorcing after 4 months. Claims that he has been blackmailing her for 500million krw (~$500K) or real estate property for divorce settlements, otherwise he would reveal their past marriage which is her private life.
Maybe he felt like this was his last chance before they left for Greece.
(female volleyball players in Korea are treated like idol celebrities and held to that same standard too, so revealing their marriage would've been quite bad for her, also for her personal life)
Still surprising she used to be married, but personally I'd rather not find out about an athlete's personal life (unless they committed a horrid crime and is charged in law for it), and just watch them play volley
Though, if the dude is who I think he is, I don't think DY necessarily tried hiding it when they were together, they went around together quite publicly. There were also rumours back in 2018 she wanted to retire to get married. A fan shared that back in 2019 she shared her ex-bf cheated on her so she broke up with him though. (ofc, with all stories, can be one-sided)