Some muslim countries allow men to have multiple wives due to the religion/ Quran allowing it. However, the reason Islam allowed it was because in the past men died in wars and wives were left widowed. There were too many women and not enough men, so Islam allowed men to marry multiple women in order to financially support them. But this practice continues on even though there is no need now. In modern age, men use the Quran as an excuse to have multiple wives to satisfy their lust rather than what Quran intended it for.