With celebrity couples breaking up left and right — not to mention her own split from Nick Lachey in 2005 — it’s no surprise Jessica Simpson is having fiancé Eric Johnson sign a prenuptial agreement before their November 11 wedding.

But with her billion-dollar empire at stake, Jessica, 30, isn’t taking any chances, and has put a strict no-cheating clause in hers. “Jessica’s biggest fear is that Eric will stray, so she insisted on that specific clause in her prenup,” a friend reveals.

This should put a stop to all those dumb blonde jokes, right? “She’s being fair with Eric in case things don’t work out, but he won’t get anything if he cheats.”

For access to all our exclusive celebrity videos and interviews – Subscribe on YouTube!