I doubt that monogamy has been around for most of civilized history. Is there a correlation between the Christian church coming into power and monogamy? How did accepted sexual behaviors change as major powers changed? My guess is this could be related to the witch hunt period of history, am I correct here? *edit: I'd love to hear from different experts on different times of history. I realize this is a broad question and any direction you'd like to take your answer is welcome.
The Greek and Roman world had formal monogamy (only one licit relationship was recognized, though the wealth continued to have intimate relations with slaves, people generally visited prostitutes, there was infidelity, etc). Here's an interesting, short review of the subject. One of the big questions is how do you count socially recognized, but legally unrecognized relationships? In the Illiad, the male characters only have one wife, but they still enjoyed extramarital relations with unfree women informally, "you have many women in your huts, chosen spoils that we Achaeans give you first of all, whenever we take citadel". While Priam, King of Troy, had three wives, the Greeks clearly and unambiguously each only had one wife who could produce legitimate heirs. The author of the review points out that this was kept with various levels of strictness in the Greek world across time and space, with some places sometimes recognizing the offspring of free men and unfree women as legitimate under certain circumstances. Still, monogamy was an important part of "being Greek". Romans followed much the same social rules as in marriage.
So, rather than attribute this aspect of Western Civilization to Jerusalem, it should more properly be attributed to the other two nodes of our canonical triumvirate, Athens and Rome. Indeed, as late as Augustine, monogamy was referred to as "Roman [rather than Christian] custom". Indeed, several times in Christian history (the Anabaptists at Münster, the pre-1890 Mormons) polygamy was "restored" by rebellious groups who sought to "restore" a Holy Kingdom more generally. However, this goes to emphasize how extraordinary such a move was writhing Christianity. I'm aware of no Christian region that formally accepted anything other than monogamy (as I said, excepting these few, theologically isolated groups), which shows just how normative monogamy was for Christianity as a whole even though it was originally a Greco-Roman custom. By comparison, though as early as Qumran, Jews spoke out against polygamy, Jews only began adopting formal monogamy as the exclusive arrangement since Rabbi Gershom c. 1000, and initially only in Christian dominated lands. In Muslim lands, Jews slowly abandoned polygamy over the next several centuries, though pockets remained in among the Jews of Yemen until very recently (either the 19th or 20th centuries).
The norm where? Polygamy (either through direct plural marriage or through legitimized concubinage) was the norm throughout most the Islamic World, West Africa, South Asia, Southeast Asia, China, Oceania, and the Amazon until the 20th century.
In the West, polygamy was accepted by Northern European nobility at least as late as the eleventh century. King Cnut of England married Emma, widow of the former king, in 1017, without making any effort to divorce his first wife Alfgifu.
In early modern France, and until the revolution, a king's mistress was essentially a legally-recognised position. But the maitress-en-titre was not expected to be faithful, as contemporary Ottoman concubines would have been. Many French mistresses had husbands despite their formalized relationship with the king.