There are a number of factors at play.
Liberalism has the net effect of turning people into animals. Therefor, human behavior begins to be motivated by basic animal instincts. By basic animal instincts - women want their brains ****ed out - and just about anything that gets the juices flowing beforehand will be pursued.
When you have societies that have been encouraged to follow basic, primal instincts - you get boys who act like small territorial warlords who try to knock up as many girls as possible while taking responsibility for none - and girls who spread their legs for anything that makes them tingle.
There are other instincts - women do have the need to be taken care of and protected - we have a government that pays the bills for them, now - and there are plenty of guys out there trying to buy influence with a girl to try and take care of the other things. It's not necessary for women to actually select a stable mate, and little need for men to appeal to those senses.
Case in point - while working in fast food, I see a lot of girls driving their boyfriends through the drive-through and paying for the meal for both of them... and even when the guy is driving and it does appear to be his car - she is still paying for the meal. It is too disproportionate for it to be a sign of egalitarianism - of women and men splitting the costs of living. The girl is the one who is the bread-winner in the relationship and the boy is simply along for the ride.
Boys trade their mom for a girlfriend - and this behavior has been encouraged by society.
Watch any prime time television show made within the past 30 years. Older males in these programs are portrayed as macho idiots and buffoons. The father is generally in conflict with the mother - the parents in the house act like they hate each other and the children are almost always portrayed as being more competent and sensible than the parents.
The general idea has been to destroy the core family - of a unified mother/father household and to completely destroy the image of healthy males in general. The traditional role of the father within the family has been to provide stability. He is what happens "when your dad gets home" - he reinforces the mother, he earns the bread well enough to allow the mother to fulfill her maternal instincts without undue pressure, and to pursue a career of choice as opposed to a career of duty. He is the peacemaker and the arbiter of justice within the home, quelling storms of emotion and conflict.
That is the traditional role of the man in the household - even if not everyone who sets out to fulfill that role does so with the best of performances.
By turning this role into a mockery, the liberal media has successfully destroyed the core family within the minds of an entire generation. It is no longer seen as an important concept, nor is it seen as something that should be pursued.
This will all eventually default and reset. It can't be maintained, and the societies experiencing it will collapse.
In the mean time, however, it is why girlfriends put up with guys who steal from them, break their stuff, and cheat on them. The image of what they should aim for has been so thoroughly destroyed that they don't really have anything to set as the objective standard. Or - worse - they do not believe they are deserving of the objective standard and thus never allow themselves to pursue it. I've seen that quite a few times - women who are wonderful people and would make wonderful partners who believe they are lower than dirt and thus incapable of finding anything other than the pond scum they are with (and even seem to reason that the pond scum is punishment they deserve for being who they are).
It will all get straightened out, but only after society has abandoned its foolish fornication liberal insanity.