STICK a fork in him – MATT LAUER is done on “Today”!

After years of clashing with his co-anchors, and with the NBC morning show’s ratings tanking, the 54-year-old TV veteran is getting the boot, sources say.

“It’s just desserts. Matt is finally getting what he deserves!” a Studio 1-A set insider told The ENQUIRER.

“His years-long feuds with former co-hosts Katie Couric, Meredith Vie­ira and Ann Curry have taken their toll. Everyone has turned against him, and Matt is going to be ousted because he’s being blamed for the show’s collapse.”

Longtime ABC rival “Good Morning America” now sits atop the morning show ratings after leap-frogging over “Today” when Savannah Guthrie replaced Curry as Lauer’s co-host – but insiders fault Lauer for the slide. “This prob­lem is not going to go away until Matt Lauer does,” a “prominent” former NBC News exec recently told a Big Apple newspaper. “He’s great, but fairly or unfairly, his brand is damaged.”

In the first step toward dumping Lauer, network bigwigs named a new producer at “Today” to re­place an executive who was a longtime Lauer supporter.

And NOW sources say well-liked weatherman Al Roker is secretly plotting to push Lauer aside, and will lobby the new boss for help.

“Matt and Al used to be good bud­dies – until Al found out Matt had been instrumental in Ann’s ouster,” said a “Today” source. “They come across as friends on the air, but that’s all an act.”

As The ENQUIRER reported, Roker even made an on-air crack seemingly aimed at Lau­er about “throwing one of them under the bus.”

Roker has been campaigning for 37-year-old Willie Geist – who was recently named co-host of “Today’s” 9 a.m. hour – to take over Matt’s seat, said the first source.

“Adding a fresh new guy like Willie to the mix is just what Al feels ‘To­day’ needs to help pull the show out of the ratings doldrums and compete with ‘GMA,’” the source explained.

The shake-up has put Lauer’s big-bucks contract – a $21.5 million-per-year deal – on the line, sources say, and his womanizing has also come back to haunt him.

Lauer’s roller-coaster marriage suffered a near-fatal blow in 2006 when wife Annette – then pregnant with their third child – filed for di­vorce. The legal action came amid rumors that he’d gotten involved with married “Today” news anchor Natalie Morales during NBC’s cov­erage of the Winter Olympics in Torino, Italy.

Annette eventually withdrew the divorce filing, but her fears about her husband’s roving eye were well-grounded.

As The ENQUIRER has reported, Lauer carried on an affair with Jes­sica Thorman, a married Florida woman, until just months before his 1998 wedding to Annette.

Her husband, Zoltan Molnar, accused Lauer of wrecking their marriage, and declared: “Matt is not the goody-goody nice guy he looks like on TV.”