Actually, there tends to be no scripture in regards to that teaching. I tend to believe that just became commonly accepted in morality and just evolved. One can note that even Abraham had multiple wives, but he was a Jew. How many sons and daughters did he have? I mean, seriously, can you think how that would have been if he only had one wife? There has been first wives and concubines. Considering how dangerous birthing was back then.
The fascinating thing to think about however, is the fact that when Christianity was Europeanized, there was a movement toward ascetism at least outwardly while profiteering. In that sense, there was also a prevailing belief that taking a young boy was less sinful than taking a woman within the clergy. Many were advocates of the Fire and Brimstone approach in preaching while living a hypocritical double life behind. One can mention the Borgias as a quick example of excesses. Perhaps that might have been a factor towards the monogamous approach.
Besides, what do I know? It is not as if I lived in that era and went through the slow shifting changes in morality, or could even be a change due to confusion in ascendancy, who is a bastard and who can inherit. Scripture was disputed, and it is also fun to note that there are more versions of a particular scripture, than there are words to them. Which is why there were wars and dischord back then within the factions of the church till a group finally won to the make up the canonical version that is now the new testament. Chapters and verses were added by a French man, I believe in the 14th century, certain parables were added from foot-notes and stories were taken out. Any how all other scriptures were deemed heretical and many who owned them were put to the stake. Hence, knowing the history and reading for oneself, to think for oneself is necessary, as taking spoon-fed teaching is lazy and one can easily be led astray.
Oh! As for being chauvinistic, that is due to shifting public consciousness and that people are now more free to question than before. What is common practice before is being scrutinized, as it should be else progress can not be made. This is the reason there are a lot of variations from the christian faith, since not everyone can agree on one particular thing. Besides, one can be chauvinistic in more ways than one, what you are asking is merely one part of it. So what if monogamy is practiced? If you look at the marriage contract, it favors the males quite a bit before, and perhaps even up till now. In truth, I really don't care, but your question misses the greater issue as it looks at only one part of the whole, making the vision myopic.