Indonesia's constitutional court has blocked an appeal to allow greater freedom for men to practise polygamy.
The court said its ruling protected women's rights
The case was brought by a Jakarta businessman who argued polygamy restrictions contravened his rights as a Muslim.
Indonesia allows men to marry more than once with the approval of a religious court under certain constraints.
These require the first wife's consent for the second marriage before the court will approve the application.
Mohammed Insa argued this restriction deterred many men from registering second marriages, which in turn meant children from unregistered marriages could lose inheritance rights and other benefits.
But in its ruling on Wednesday the court said the articles were against neither the tenets of Islam nor the country's constitution.
"These articles ... are intended to protect the basic rights of wives and prospective wives of men who engage in polygamy," said Jimly Asshiddiqie, the constitutional court chairman.
Mr Insa said the decision was unfair.
"I'm not happy. With such conditions, polygamy cannot be practiced," he said. "I will continue my struggle with other people or groups."
The polygamy debate in Indonesia, the world's most populous Muslim country, heated up last year after a popular Islamic cleric, Abdullah Gymnastiar, caused uproar by announcing he had secretly married a second wife.
The cleric was seen by many as a model husband and a promoter of family values.
Indonesia's mainstream Muslim parties argue that restricting the practice, which they say is sanctioned by the Koran, will lead to increased levels of adultery.
Under current laws, Indonesian men are allowed up to four wives with the approval of an Islamic religious court - but only if their existing wives are disabled, terminally ill, sexually inactive or infertile.
But these restrictions are rarely enforced.
Though not widely practiced among ordinary Indonesians, many observers believe polygamy has increased in recent years, while others say it has simply become more open.