I was 32 the first time and still got it wrong! :-)
Actually it wasn't so much I got it wrong but I married for the "wrong reasons". This was during a time when single men of that age were being accused of "fearing commitment" I guess I wanted to prove I wasn't afraid of anything. Awhile back I wrote a hub titled 5 Reasons Why Me Should Not Get Married. http://hubpages.com/relationships/5-Reasons-Men-Sh...
The marriage helped to shape my philosophy and my understanding that "Life is a personal journey". "You are responsible for your own happiness."
From then own I made sure my decisions were "my decisions" and not those of someone else. I began to compromise less and less and started to look for people who "naturally agreed" with me on the major things in life. I had been making my life more difficult by trying to "persuade" or "negotiate" with others who did not want what I wanted. You are far better off waiting for someone who (already is) they type of person you want to be with than trying to get them to become that person and vise versa. I came to realize there was no "right" or "wrong" but rather it was about "agree" and "disagree". I became more careful and aware of my choices and decisions (while I was making them). If a relationship failed instead of simply blaming the other person I looked at (why I chose them) to begin with! After all each us of "chooses" our friends, lovers, and spouse. That marriage provided me with a priceless education!