Why do people have impossible standards for marriage?

I don't.

I'm also married way longer than the average. My husband and I follow the Wheaton Rule, and it works really well.

So define your 'impossible standards'.

Yeah you need to explain this premise. Its vague right now. You might be right but please layout your explanation in more detail so we can understand what you really mean by this.

What do you mean by impossible standards?

You have already skewed your research by calling standards "impossible."

Double standards in marriage.
http://www.allprodad.com/7-common-double-standards-in-marriage/

Before we got married, we talked to the buddhist minister's wife whom I've known before WWII, because we were buddhist. While in concentration camp, they lived in the next barrack to ours in block 27.

When we met her in Mountain View in California before our wedding, she told us that after a few years, the grass is going to look greener on the other side of marriage. But, she said, if you get divorced and marry again, the same thing will happen in your second marriage. So, the conclusion is, if you have difficulties in your marriage, work it out!