Why do women start the majority of divorces?

Here’s an article about the subject.
http://www.startribune.com/lifestyle/relationship/11329451.html?page=all&prepage=1&c=y#continue

Statistics show it is much more likely for the wife to file for divorce 70% to 30% for the husband.
Why is this ?

Adultery is split 50/50 between the sexes as a reason to file for divorce,so I know its not that. So what is it?

Are we men just so bad at it?

Are a women’s expectations just too high?
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