Best friends do everything together ... and in the case of the Arquettes and the Harpers -- they even call off their marriages around the same time.
Back before the two power couples each called it quits -- the foursome spent a whole lotta time together throughout the years ... because Laura, Ben, Courteney and David were all best friends.
So David and Courteney separate several months back -- and suddenly Ben pulls the plug on his marriage. Coincidence?
Arquette/Harper-- Weird Coincidence
10/11/2010 7:07 PM PDT BY TMZ STAFF
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