SEOUL, South Korea — Two of South Korea’s pop idols, HyunA and E’Dawn, have learned of the painful cost of falling in love and declaring their relationship in public: On Thursday, they were fired by their management company.

The two performers’ falling out with their Seoul-based label, Cube Entertainment, opened a rare window on the jealously guarded world of K-pop stars, who go through highly regimented training from an early age, and on the companies that help them build worldwide followings.

“No dating” clauses were once common in the contracts of young K-pop stars, according to industry experts, with many managers saying that publicly disclosed romances would undermine their idols’ allure and careers. Avoiding romantic relationships, or at least keeping them secret, remains an unspoken rule.

So HyunA, 26, one of the genre’s most recognizable female stars, and E’Dawn, 24, a boyband rapper with a smaller but still substantial global fan base, took a highly unusual step in going public with their relationship last month, contradicting an earlier denial by Cube.