my theory on why women go from being compassionate/loving/fair/loyal as children to satan's shallow demon imps
when a girl is young, she is usually a tender & loving being, and does not yet distinguish weak men from powerful men
as she enters puberty, the instinctive desire for reproduction kicks in -- although at this point, she still does not favor powerful men entirely over less socially assertive compassionate men; since her body is still young, she may still favor the compassionate man as someone giving support as she gets older (both emotional support and other forms of support)
However, weak vs powerful does not necessarily distinguish between attractive and unattractive, and the desire for physically attractive men is perhaps at its most potent period during early and middle puberty (for a number of reasons, such as physical attractiveness being at its most accurate as an indicator of a person's genetic quality during these years when the body's genetic aptitude is being put to the test).
During the final years of puberty, the vagina figuratively backs up into the brain, transforming women into the deceptive persuasively-curved hell-spawn that most eventually become. It is now no-longer optional but required for a woman to find a man who can provide economic support, and must thereby take in a lesser-male (more often referred to as a "beta male"). The woman then compares herself to the status of other women, and holds the lesser-male sexually accountable for any deficits; she then channels her malcontent with the lesser male as an excuse to secretly acquire sperm from the alpha male. Whether this is morally right or wrong is instinctively blocked out by the woman's subconscious, and she need only a faux social justification in the back of her mind as sufficient-enough reason to acquire alpha sperm.
This drive to seek out and acquire alpha sperm unbeknownst to a lesser male partner is not an uncommon event in the least, but is almost instinctively mandated, as sexual selection has dominated the course of human evolution for many many millennia, and is genetically hard-wired into this.
The occurrence of this phenomenon seems to be so common that it should in fact be considered the standard, and instances of spousal faithfulness are actually the exception.
Now, although I believe in all that, I do also believe in the existence of a "true love" phenomenon in which the aforementioned cycle (and simple variations of it) will break and not occur. The phenomenon of 'true love' is actually superior to other types of sexual relationships, but it can not be attained forcefully.
Such relationship where both parties have a deep-seated affinity for one another requires the male and female to be at the same level of sexual experience when they first meet, as this creates a bonding between them. The reason this fails to occur so often is due to the alpha effect: a single alpha male may have sex with dozens of girls each year, while lesser males may have only a small handful of sexual partners in their entire life - or perhaps just one, or even none at all. This leads to a snowballing effect in where the vast majority of women will lose their virginity many years before most lesser males do.
In our modern society, it has become incredibly easy for the alpha effect to take place, due to technological advancement aiding people in communicating, as well as the existence of government-aid for single mothers which kids, which enables them to do this.
Due to all of this, a large percentage of males will end up being partnerless, or being the host for a woman with children from other men.
This causes the males of the population to live extremely disatisfactory lives, so the women can carry out their instinctive practice of sexual selection and make the human race more attractive looking (rampant with giant penises and uselessly massive breasts). In its most severe form, the only way a society could develop the process any further would be having full-out eugenics take place (as happened occasionally in ancient times). As it is, society carries out a silent eugenics, orchestrated by women.