How come everyone talks about how shit their ex is? "She's a bitch. He's an asshole. She's insane. He's a loser." Pretty rare that anyone admits their own failings as a spouse.
No one ever admits that they're the least bit sad about it either. They're alway 'better off without her' and 'moving on' with 'a new lease on life.' 
My ex is a selfish bitch and she's insane, and I really am better off without her, but a lot of our failed marriage was my fault and I'm very fucked up about the whole thing. How someone's first priority in divorce can be money is a mystery to me.
Yes this happens often. You would hope someone would learn from the experiance and use that in future relationships. Most people dont use thier head fully when getting involved. I mean you have to know what works for you. Sometimes you will overlook many of the incompatiabilitys at first cause of the excitement of a new love, the sex and the fun you are having, that initial lust or fireworks. But sooner or latter you better look at the big picture for real to see if there is a long term future there.
Too many people men and very much woman will say "If we love each other it will all work out no matter what" This is a nice notion but it came from the movies and religion so it is not based in reality. You need to know yourself first and evalute if the relationship will work for you long run, not just cause you are having good sex now.