An exhausted NICOLE RICHIE finally snapped!

The mother of two suffered an emotional breakdown in late July over fears that her fiance Joel Madden might cheat, and because she believes he has chosen his work over marriage to her.

"Nicole is at her wit’s end," an insider told The ENQUIRER.

"She feels like her personal life is imploding. Besides everything else, she can’t keep up with her work demands.

"She barely gets four hours of sleep a night."

Losing it, Nicole sobbed to a pal last month, "I can’t take this anymore!"

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