Do You Fake It With Your Significant Other?

I am just getting around to reading the November issue of Redbook (I've been busy).  On page 25, it says that 71% of wives have faked it with their husbands. That is shocking to me.  My first thought is "why?"  I don't understand the reason behind faking orgasm with a person you are supposed to be honest to and close with.  Maybe I am just spoiled from a guy who doesn't finish until after I do.