Hold off on that engagement gift for Cameron Diaz and Benji Madden! Even though the couple are headed to the altar after seven months of dating, things are far from blissful.

Now Cameron and Benji are battling over the details of their prenup. "At stake is Cameron's $90 million fortune," an insider reveals. It's exponentially more than the Good Charlotte rocker's $20 million net worth.

"Benji's pride is hurt," the insider says. "Haggling back and forth over money only highlights how much more successful Cam is. He's worried that signing a prenup will shift the dynamic in their relationship."

It seems like it already has: "Cam shelved all wedding planning," the insider says, "until they resolve everything!"