Biologically as far as men and women being naturally monogamous or not, I think that it’s not that simple. People are very complex. I think that most people have a tendency to want a lifetime monogamous relationship AND they also have a desire to sleep around. In any random sample of people you will probably find people who lean heavily toward either end of the spectrum and many somewhere in-between. Purely as a male reproductive strategy, one-night stands, trickery, seeing prostitutes and even rape and incest have proven effective at passing one’s genes. If we all could se our entire family trees/heritages, I bet we would find that all of us are the product of these modes of “reproduction”. No matter how strict or lenient the laws, taboos, sexual expectations or religious demands, people end up reproducing one way or another. In times of war, famine, slavery, depression, uprising or prosperity, people end up reproducing one way or another. This ingrains in all of us very complex sexual desires and behaviors.
I think at least half of all people shouldn’t seek marriage, men and women included. Anyone who is naturally: selfish, greedy, unfaithful, dishonest, violent, unrealistic, or has a problem: going ballistic, with drugs or alcohol, etc. probably is going to make a poor spouse. It’s no surprise that so many marriages end in divorce; most people aren’t marriage material. Lasting until death do they part is no guarantee that the couple had a happy, beneficial marriage either. I think nearly all marriages have some rough times and issues, but it is a very good thing for many people.
Saying that men should not seek marriage, however, is like saying that people should not seek being professional athletes or entertainers because the majority who try fail. The big difference is that if you fail at becoming a pro football player or rock star, you simply move on. Fail at marriage (even if it’s not your fault) and you will probably get burned financially for decades and quite possibly emotionally as well. If you have children you will probably get burned even worse.
To have a successful marriage you must be worthy of marriage, choose well and work at it.