Birthday party disaster lands BARACK OBAMA in the dog house with furious FLOTUS. PLUS: Her $100k full body makeover for post-divorce life!

PRESIDENT Obama’s desperate attempt to heal his shattered mar­riage by throwing a spectacular 50th birth­day party for first lady Michelle turned into a disaster – and now she’s moving full-speed ahead with plans for life after their divorce, including a $100,000 makeover, say sources.

As The ENQUIRER revealed, the first couple’s 21-year union has been rocked by the president’s wandering eye – and they recently got into an ugly argument after Michelle learned that the Secret Service has repeatedly cov­ered up her husband’s cheating.\

Obama hoped he could make amends – and get himself some much-needed positive public relations – by throw­ing Michelle a star-studded birthday bash. The Jan. 18 celebration was at­tended by some 500 guests, including Paul McCartney, Smokey Robinson, Jennifer Hudson, James Taylor, Bill and Hillary Clinton, Michael Jordan, Al Roker, Stevie Wonder and a host of other A-list names.

But sources say that the president’s plans backfired after Michelle demanded that they have a dance and dessert party and inserted a line in the invitation advis­ing guests to eat before they came.

“Michelle refused to have have a formal dinner because she didn’t want to sit next to Barack and make small talk all night as though nothing at all was wrong in their marriage,” revealed a close source. “They got into a screaming match over it because Barack wanted this to be a carefully orchestrated event to fool the world into believing that all is right in their marriage.”

Making matters worse, Michelle insisted that the invitation include a line reading: “Please, no cameras or photographs!”

That was a direct smack at the presi­dent, who had humiliated Michelle just weeks earlier by taking a “selfie” photo with the sexy blonde Danish prime minister at the memorial service for South African icon Nelson Mandela.

“Barack was hoping for positive PR and wanted their guests bombing so­cial media with images of the couple looking happy,” said the close source. “But Michelle refused to take part in the ‘spin plan.’ And after the party, Mi­chelle stormed out of the presidential bedroom. Instead of sleeping with her husband, she hung out with some of her closest pals in another part of the White House and they talked about old times into the wee hours.”

Now that the first lady has turned 50, sources say she is determined to live her life her way. She’s already started fine-tuning her body, adding yoga to her intensive workout routine to “keep me flexible,” she told an interviewer. And the next likely step is cosmetic surgery. Renowned Michigan-based cosmetic surgeon Dr. Anthony Youn says that a chin implant would be a good start.

The expert, who has not treated Mi­chelle, told The ENQUIRER: “Her chin is a bit small and causes wrinkles when her mouth is closed. A reason­able-sized silicone chin implant would create better harmony in her face and make her even prettier. It costs around $5,000.

“Botox injected into her forehead and the crow’s feet surrounding her eyes would smooth out the wrinkles and cost about $500.”

The physician also recommended Restylane filler injections (about $1,000) and a skin-tightening treatment (about $2,000).

Disclosed a friend of Michelle’s: “Her makeover doesn’t end with plastic surgery. She has enlisted high-profile experts for advice on her wardrobe and body as well as facials, massages, manicures, pedicures, hair­styles, nutrition and personal training. She figures to spend $50,000 on her wardrobe, including designer dresses, pants, blouses, blazers, skirts, shoes and ac­cessories. And that’s not even counting the $10,000 she’ll be spending on sexy lingerie.”

To pamper herself, Michelle also plans to spend a few weeks at a beauty spa, receiving a variety of expensive treatments, including an exotic $7,000 peel and baths in imported Evian water.

“When you add in the cost of travel and accommodation, she’ll spend well over $100,000 – and it’s all because she’s so furious at Barack’s cheating ways,” said the friend.

The president further inflamed an already irate Michelle on Jan. 14, shortly before her birthday. Still stung over being humiliated at Mandela’s memorial service, sources say Michelle hit the roof after her husband shamelessly ogled pro basketball star Dwyane Wade’s fiancee, actress Gabrielle Union, when the world champion Miami Heat visited the White House.

“He stared openly at her,” said a source. “It was so obvious that one Internet website described him eyeing her as if ‘she were the last hot dog at a cookout!’”

Previously, sources say Michelle flew into several jealous rages over her husband’s infatuation with “Scandal” star Kerry Washington.

All the fighting and feuding has left the Obama marriage hanging by a thread, and as The ENQUIRER recently reported, Michelle is already said to be huddling with divorce at­torneys. What’s more, the first lady has told close pals that she’s found a new home for her and her two girls in Washington, D.C., for their post-White House days. At the same time, Obama intends to resettle nearly 5,000 miles away in his native Hawaii where, as The ENQUIRER disclosed, he report­edly plans to live with his longtime pal Bobby Titcomb, who was arrested for soliciting a prostitute in 2011.

Michelle will remain in the nation’s capital until the couple’s youngest daughter Sasha, 12, finishes high school. Daughter Malia, 15, is a high school sophomore and likely will be in college in 2016.

During that time, Michelle will con­tinue making herself look spectacular for her new life as a sexy, single mom.

“Barack is going to be kicking himself when he sees what he’s lost,” said the friend. “But he has no one to blame but himself!”