This was a response I wrote for @Audiofox's question, "why does the "wall" exist for women but not for men?", upon writing I realized how long it was and thought it would be better to just put it in the form of a mytake instead of half a dozen responses. Its my first mytake so I apologize if it comes off as amateurish.
So the reason why women are more affected by the wall is simply because men gain over time and women lose over time. Thats not to say a mans desirability period is infinite, its not, but men gain in the long run, women in the short run. Basically it has to do with what women want and what men want. Women want resources, pregnancy is resource intensive and hinders a womans ability to acquire resources. So when looking for a long term partner she will look for a man with resources. This benefits the older man as he has a greater amount of time to acquire his resources, to build a nest egg or career or to move up the social ranks. The more time he has to do this(and ambition which is why women love an ambitious man because it means greater resources down the line) the more resources/status he can accumulate.
Meanwhile for men they are looking for women who are able to reproduce sucessfully. Reproduction for women is far more physically intensive for women then it is for men so for a woman her body is the means by which she barters when it comes to reproduction and relationships. Thats why men go after certain types of women, for instance men liking big butts is actually about the womans ability to survive the child birth process with minimal damage(as even after birth the baby is entirely dependent on the mother for food for at least two years so if any complications arise the child will almost certainly die as well).
An example of the male desire for a physically robust body of a woman would be for example, liking bigger butts. Generally speaking it mean wider hips which of course means easier birthing but it also means a greater spinal curvature( of the lower spine) which actually helps function as a counter balance for when she is pregnant meaning less strain on the body and thus less wear and tear allowing for the greater probability of multiple births without real issue. This is why men are obsessed with a womans body, because it determines her ability to survive child birth. However time wears the body out for both men and women, that means the older a woman gets the harder pregnancy will be on her body and the longer it will take to recover and the greater the probability of complications(thats not even taking into account that older women are more likely to give birth to babies with genetic defects like autism and what not).
Then you have the issue that a man can, theoretically, be able to reproduce up until the day he dies with minimal issue, a woman however has a finite time to do so, after menopause she will be completely sterile. So time works against women and for men it works for them.Then you have the issue that men are against promiscuous women, they are willing to have sex with them as it means increased probability of reproducing but they are far less inclined to have a relationship with them becuase it increases the odds of raising a child(highly resource intensive) that is not theirs and potentially taking resources away from their own child thus reducing the likely hood of their child surviving to reproduce themselves.(this is also why women are less against promiscuous men because maternity is never in question for a woman, she is always aware that she reproduced the man is not).
Neotenous biological traits also are to be taken into consideration. These traits basically are traits that are held over from childhood, we all have them but women have more of them, for example thinner skin(25% thinner to be exact) which makes their skin softer, less muscle mass, less prounounced bone structure in the face, greater amount of and narrower channels for tears making women biologically more capable of crying then men etc. All of these trigger a response in our species that is very similar to that of our response to children, in short its something that incentivises us to protect women because of their similar traits with children(thats also why we find cute things cute, they have traits that are similar to our own young i.e. big eyes, over sized head etc). As women age however they begin to lose these traits, or rather they become less pronounced, this means that women get the strongest responses from men when they are young but as time progresses men are less increasingly less inclined to go out of their way for these women(not that they are mean to them but rather they are no longer as inclined to give them special privileges, or prioritizing these women over others).
Men also lose collagen(the substance that gives your skin structure) less quickly then women do at a rate of 1% a year after the age of 30 comparative to 2% a year for women(obviously how well you take care of yourself also affects rates). In addition men have greater muscle and bone mass/density then women which means that as time progresses they may lose that mass at a same rate but because they have more of it their bodies remain relatively resilient comparative to women thus giving them a longer period of time of "viability", or sexual attractiveness and resilience.
So all of these combined create the "wall", a point in a womans life where she becomes less desirable then before. This of course was not a problem before as we had marriage. Marriage was what helped prevent this phenomenon from occuring, women married young when they where most fertile to men who could take care of them, they married young and because sex outside of a marriage was seen as taboo these women would not be promiscuous so their was not wall. Now these women sleep around(not necessarily their fault they are told there are no consequences for it when their is most definitley consequences for it) which makes them less desirable for long term relationships, they live it up in their younger years when their neotenous biological traits are their most pronounced thus resulting in men being far more generous and amiable to them on top of having greater reproductive potential(this is why you will not see men buying drinks or showering old women with attention, they lack these things) but as time progresses this attention begins decreasing.
But then as time goes on they lose these traits and become increasingly more risky investments for reproduction as they age because again, increased risk of birth defects, death, and sterility, as well as many of these women slept around meaning an increased risk of providing for some one elses child which men are biologically inclined to avoid(not to mention the increased risks of divorce, cheating, unhappiness in long term relationships etc. which many studies have shown also occur). However as time begins running out these same women begin to realize the effect time is having on them and they realize they want a family they want a relationship so then they make a mad dash to find this before time runs out.
Men have now seen how this works and seen that rushed relationships like this with women who have never really been inclined towards them before ends poorly and thus have given the name of this phenomenon "the wall" the point of no return so to speak. That's not to say men do not also have a time limit only that these things do not affect us ad much so our "wall" is far less prominent and is rarely an issue to us as once we exit our youth we generally leave it with more resources then before and along with women being less against male promiscuity, have a less difficult time acquiring that relationship and family.
This is not me trying to preach, do with your life as you see fit, it is after all your life. However your actions do have consequences and while you may not like them, you may think they are "unfair" however that will not alter the fact that they do exist and you will experience them. As such its better to make an informed decision which in defense of all these women who have reached "the wall" they have not been properly educated on the matter like they should have been. People are not informed of this and told to live it up only to find out later in life that their was a reason our ancestors where against this mindset.