And this is so not what happened.
It is a matter of historical fact that successful Greek men, in Athens and the region of Boetia and other locales, who were not homosexual but rather pansexual paedophiles who engaged in institutionalized pederasty and institutionalized marriage of teenage girls at an age that was common at the time but unacceptable at present, did marry girls who were typically fifteen years of age on average (this was also the case in Rome, unfortunately), and also took as lovers boys who were usually thirteen years of age, and would live with the men until they turned seventeen or eighteen, around the time they started to develop mature facial hairs. Later they would repeat this cycle of abuse. Fortunately this is not a problem we contend with today.
There is also the well documented Theban elite military unite known as the “Sacred Band” which consisted of men and their teenage lovers, which was noted for its prowess in military combat.
In ancient Rome, this kind of institutionalized pederasty did not exist, at least among free men, but it was regarded as entirely acceptable to engage in relations with slaves. What was unacceptable in Rome was for a man in a position of power to be the passive partner in such perverse relationships, and this is why they tended not to occur as frequently between freemen and natural-born citizens, but rather occurred where there was a power imbalance to begin with, between adults and slaves. It is also the case that most Roman baths also operated brothels that catered to what one might politely call a variety of tastes, and some Roman baths allowed men and women to bathe together at the same time (but not to engage in public relations; in ancient Greece however Diogenes engaged in self-abuse in public, among other behaviors he engaged in for shock value).
It is also, according to Muslim sources, the case that Muhammed married Aisha when she was six, and consummated this marriage at the age of nine, which is well below the minimum age for marriage in the ancient Hebrew religion. Now it is true that Aisha, according to those same sources, did become in love with Muhammed, and was the most upset when he died (allegedly, according to some Hadiths, due to being poisoned by a Jewish woman; this may be anti-Semitic propaganda, that is to say, actual blood libel), but if this is true it would not excuse Muhammed for marrying a nine year old.
Christianity has historically rejected most of this; the increase in the age of consent for marriage however is more recent, but the youngest age at which any Christians were allowed to wed was historically twelve for females and fifteen for males. This is still too young, but it is not as perverted as Islam, and we can regard this to some extent as an artifact of society at that time, with shorter life expectancy among other issues. Christianity (with the exception of some heretical sects such as some Gnostics, who are not regarded as Christians according to the CF.com statement of faith) however was always opposed to non-procreative sex, adultery, polygamy, homosexual marriage, incest, and prostitution. Indeed prostitutes and pimps were required to renounce their former profession, along with gladiators, actors (the Roman theatre scene tended to be highly licentious), and teachers of Pagan philosophy. However, to preserve family units, polygamists received into the early church were not required to divorce any of their wives, but they were permanently disqualified from Holy Orders (being ordained to any ministry).
Everything I have stated is factual to the best of my knowledge and is exceedingly well documented.