Islam allows multiple wives. The Koran teaches that men are allowed to have four wives but only if they can financially support all of them. Men with multiple wives can be found in certain Muslim societies in the modern world, but these men are usually wealthy.
In Islam, a man does not need permission from his first wife in order to wed another woman, but the woman must explicitly forbid that he cannot take another wife before she marries him. Polygyny is still found in such places as Saudi Arabia, including the Islamic parts of East and West Africa. Many secular Islamic societies frown upon polygyny, and some Muslim nations have made it illegal. The practice of keeping multiple wives in Islam is also viewed as outdated by many young Muslims.