Marriage is a partnership, but just how much should each person put into the union? 50/50? Love and support split right down the middle?

Not so, wrote Karl A. Pillemer in a recent blog post on Huff/Post50 on the myth of the 50/50 marriage. In the hopes of understanding why some marriages can last for decades while others falter and end in divorce, Pillemer interviewed more than 1,000 long married older couples to find out about their experience with marriage.

Kay, married 54 years ago, summed up the reoccurring advice Pillemer encountered:

"Okay. It's not a 50/50 proposition. It's a 90/10. Sometimes you're on the 90, and sometimes you're on the 10. That can vary, depending on where you are, what's the issue on the table. But anybody that goes into marriage saying, "Oh -- this is going to be 50/50," it doesn't happen. You can't live in the same house with the same person all those years and always divide it down the half."

It takes a lot more than that to have a long, successful marriage, Huff/Post50 readers said in the comments section. See what readers had to say in the slideshow below.

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