Why do most marriages fail?

Because you both get fat and ugly and your personality gets rotten as well.

Thank goodness both the wife and I stay in shape and she sexes me regularly.  Married 23 years so I can talk as much smak as I want.

Plus, I earned the privilege for side action if I ever need it, the wife says.

Marriage is hard work.  You have to give, give and give more.. and of course you take also.  But the main thing that I have seen in my almost 60 years.. is non-communication. Communication is the rock in a marriage.  Without that.. you have nothing.

Women lose sexual desire for their men. They start saying "no". Eventually this will always degenerate into disputes of some sort, until she finds what she thinks is a good enough excuse to file for divorce. Women are not naturally monogamous. Women initiate most divorces.

For the most part i believe that  disagreements about money lead the list. They all say money cannot buy happiness and that is true, however the lack of money creates problems because the world revolves around it. Secondly, accepting each others roles in the relationship. No matter what is said or pushed on society women and men are not and never will be equal. It is very rare that a man and woman can have a relationship where each can allow the other freedom to exist without trying to have them follow your direction. To enjoy the things with each other that you both like to do yet allow the other to enjoy another activity that they like and you do not is the key.

there are lots of things like porn, money problems, cheating, and also agreements and being married at a young age, I have never been married but I can tell you that I think porn is the main one why marriages fail. 

I think it really comes down to people having different experiences/expectations, and people pretending to be someone they're not at the beginning of the relationship and then changing later. I think this can be best described as complacency. People start to become unappreciative when they've attained something. Most people view each other like objects, whether they realize it or not. When you get a nice shiny new car, for the first few weeks you're in love with it, and then six months down the road it just becomes another car to you because you're so accustom to it. This is how the majority of people view relationships/marriages as well.

Trust and the ability to resolve conflict.

Lack of trust is the root cause, but it requires explanation because trust is such a root cornerstone of any relationship.  Trust is not just about fidelity, infidelity is a common cause for divorce, it is about believing the other person has their best interests as their own priority.   Thus issues like finances, security, parenting, and responsibility are also key factors of trust too.  Often the marriages that fail most often are between those who are too immature to be married, or simply don't see marriage as a lifelong commitment going into a marriage.  In my observation this is often determined by the socio-economic background as couples who are better off financially get divorced far less than poorer couples.

The ability to resolve conflict (or compromise) is an essential skill in marriage.  Some who get married think they know how to resolve conflict, but in reality they are in the honeymoon phase of the relationship and haven't actually come across a real conflict, or it has been small and easily swept under the rug.  Others know the skill but forget it during their marriage and don't make the effort to relearn it.  If you can't resolve conflict the little problems will snowball into big problems until ultimately one or more spouses quits trying effectively ending the marriage.

Well, the latest 2020 statistics I've seen for the U.S. says that 39% of marriages end in divorce, so it's not most marriages.

While I haven't read any statistics on the why, I do believe that a lot of the answers can be found just by looking at the questions being asked in here, both in the Marriage & Divorce section and in the Singles & Dating section.

People get involved with someone who, to the outsider, clearly isn't good for them, and yet they hang on, trying to change themselves, trying to change their partner, looking for that magic fix that will suddenly turn that other person into the perfect boyfriend/girlfriend, and many think marriage is the fix, but it isn't.

People rarely change, and slowly that infatuation/blinding love that was the reason they settled and couldn't let that other person go before starts to die, often aided along by living together, financial stress after buying a house/car/whatever, sleepless nights due to crying infants etc.

Financial issues are the biggest driver.  Then it's communication issues, fidelity, and the rest.

I'm not sure . There was a lot of gold involved it should have been good right?🤔