Workaholic Donny Osmond’s 36-year marriage could be on the rocks, sources told The National ENQUIRER exclusively.

At 56, the beloved entertainer is busier than ever, but wife Debbie wants him to slow down and spend time with their family, insiders said.

“Debbie has given Donny a marriage ultimatum to cut back his hectic work schedule – or else!” said a pal.

“Donny has promised Debbie he’d drastically reduce his schedule, but so far he hasn’t. In fact, he’s taking on more and more work!”

The youngest of the couple’s five children is close to moving out, and they’ll soon be empty nesters, said the source.

“Debbie has been waiting for this for years,” added the source. “She wants to travel the world with Donny and spend time with their six grandchildren.”

Since 2008, Donny has been performing with his sister Marie at the Flamingo Hotel in Las Vegas, and their contract there expires soon.

“Debbie is hoping that Donny won’t renew the contract, but she isn’t holding her breath,” said the source.

Donny and Marie are now doing a slate of holiday shows for almost the entire month of December with only a four-day break at Christmas. “Debbie thinks he should have taken the entire month off, but she should know by now that entertaining is in the Osmond DNA,” said the source.“I wouldn’t be surprised to see Donny up on stage singing ‘Puppy Love’ when he’s 90 years old!”