EXCLUSIVE

Jay Mohr and wife Nikki Cox are off again, because he's filed for divorce for the second time.

Mohr had filed to end his 10 year marriage in July but withdrew the petition 6 days later, telling TMZ, he and Nikki were "Very in love. Very happy and that's really all there is."

Things apparently took a turn for the worse, because he filed Tuesday citing irreconcilable differences. This time around Jay wants joint legal and physical custody of their 5-year-old son. He also says they have a prenup that spells out all the financials.