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.”

Have a tip? Send it to us! Email In Touch at contact@intouchweekly.com.