There are only 2 countries in the Middle East where polygamy is illegal: Israel and Turkey.
There are only 2 countries in the Middle East that are true democracies: Israel and Turkey. Lebanon is controlled by Hezbollah. Egypt and the rest is recent.
Has it always been like this?
Notice that Indonesia allow polygamy for Muslims, even though it's a democracy. However, thugs often enforce power and it's still very politically incorrect. Also Arab males that engage in contract marriage sometimes get kicked out if found out (even though it's legal). So it's so politically incorrect you still can't practice it openly unless you're a person with some form of influence or control.
The idea is that certain resources, such as women, land, organ, and even "excessive happiness" are too precious that people are willing to kill to get it. Hence, most societies do not easily commercialize them. Those resources are divided proportional to political power. In democratic countries, one man one vote soon lead to one man one wife.
Some article supporting it: http://www.salon.com/2011/07/23/monogamy_4/
That’s not a link I’d want to make too strongly, but it has been argued by historians that monogamy precedes, and then seems to go along with, the emergence of democratic ideals. In the Western tradition, the earliest we can trace laws about monogamy is actually to Athens when the first notions of democracy began to be instituted. The argument is that it’s meant to create equality among citizens so that, essentially, there’ll be wives available to all Athenian men, rather than having all the rich men take many wives. Although, men were still allowed to have slave concubines just so as long as they were non-Athenian women.
You can think of it as a first kind of effort to level the playing field. By saying that both the king and the peasant can only have one wife each, it’s the first step toward saying that all men were created equal.