MARIAH CAREY is begging her ailing husband NICK CANNON to quit working entirely after the hard-charging TV host revealed he's suffering from a rare form of the autoimmune disease lupus.

The 42-year-old singer is so distraught over Nick's condition — which has resulted in multiple hospital visits in recent months — that sources claim she's thinking about threatening to end their marriage and take away their twin toddlers, daughter Monroe and son Moroccan, if he doesn't at least cut back on his hectic schedule.

Though Nick, 31, agreed in February to quit his NYC morning "CBS Radio" show, he's refusing to give up other work commitments, including hosting "America's Got Talent" and his weekly "Cannon's Countdown" syndicated radio program.

"He thinks mariah is overreacting and blowing everything out of proportion," revealed an insider. "Besides that, Nick is insecure about living in Mariah's shadow, and if he quit work altogether he feels like he'd have no identity of his own.

"He hates being known as Mr. Mariah Carey."

Nick was first stricken with kidney failure in January and in February he was hospitalized for potentially life-threatening blood clots in his lungs. He revealed that the kidney condition is the result of an "autoimmune disease that [doctors] found in my system."

In early March, he further described his condition as lupus nephritis, a rare form of lupus that attacks the kidneys.

Dr. Alan Ackermann, founder of the Aventura Institute for Cardiovascular Wellness in Aventura, Fla., told The ENQUIRER that lupus is a "debilitating and devastating illness" that can seriously impact a person's quality of life. Dr. Ackermann, who has not treated the performer, also explained that lupus is sometimes fatal, and that once the kidneys are affected, the prognosis is "more dire."

Said the source: "Nick's work is his passion, but he doesn't want to lose his wife and his kids — or his life!"