In my family, of my brothers and sister and I.... 50% is the average. With me...coming up on my 3rd marriage. First one...got married at 21 before I knew what I really wanted in life and after 23 years of marriage I decided I wanted something else. My kids were in 17 and 15 and I felt secure that they could (and did) handle it well.
Second one was a habitual liar... not cheater, just lied about the stupidest things. I had to go thru her purse and drawers to find out what was really going on and didn't want to live like that.
Soon to be third marriage (I haven't given up on romance) will be the keeper. At 64 years old I have someone that wants the same things I do (although has strong opinions on some things that I have opposite opinions of) but we are great together.
For various reasons people change as they grow older. Someone you thought you could spend the rest of your life with you grow apart from in direction, wants, and beliefs. I'm still on good terms with my two ex's but now have a partner that I can see being with for the rest of my life.
For those that have only been married one time....congratulations ! For those of us that have been divorced once, twice, three times....I understand. 50% divorce rate is a fact and everyone has their own reasons why. Takes two to be in a happy marriage, but it is two people with their own desires, wants for the future. You have to find the right person, and be the right person for the other member of the marriage.