AFTER decades of performing as a duo, Marie Osmond is ready to dump brother Donny for good!

While she’s still tied to her contract with Flamingo Las Vegas, where she and Donny have been performing a 90-minute stage show since 2008, once that’s over Marie is ready to move on as a solo act, a source says.

“She loves her brother, but she can’t take all the jealousy or his controlling nature,” said a family insider.

The two have been per­forming together since childhood and rocketed to fame with their brother-sister variety show in the 1970s. But Donny has admit­ted that they’ve always been fiercely competitive.

“To make the business work, we set (our) rivalries aside,” he said in an interview last year.

But the insider notes that Donny’s public stance doesn’t hold true behind the scenes.

“Privately, it’s a different matter,” explained the source. “He’s desperately wanted to make it on his own and has recently been talking about his own TV project, which he says is very close to happening.”

Despite being a one-time teen idol, Donny, 55, subsequently struggled as a solo act and admitted on “Dr. Phil” that he’s suffered from panic attacks.

Meanwhile, his younger sis­ter continues to thrive professionally. Marie, 53, is a successful talk-show host, author and dollmaker, and she’s also been a pitch­woman for QVC and the diet plan NutriSystem. “Forbes” magazine places her fortune at more than $17 million.

“Marie doesn’t need Donny as much as he needs her,” said the insider. “But they still make a decent amount of money from their Vegas show and concert tours, which is why they re-upped their contract. But after that’s done, she wants to move on.”

The source added: “Marie has had it with Donny. She’s tired of his attitude. She’s got enough on her plate without him.”