May 18, 2007

Sometimes, even the most impressively overflowing cleavage isn't enough to save a spiraling romance. Yes, it seems that Jessica Simpson, 26, and John Mayer, 29, have gone belly-up after about six months of mismatched togetherness.

"They have broken up," a source close to the puffy-lipped, boobie-thrusting starlet tells People. "But they have broken up and gotten back together at least ten times before."

Adds a snitch to Perez Hilton, "They officially called it quits this past weekend. They'd been having problems for a while now and just decided it'd be better to end things."

It was apparently the newly shorn (and instantly hotter) crooner who drop-kicked the Mystic Tan-addicted former Mrs. Lachey, who was at the Cannes Film Festival this week promoting her upcoming "Private Benjamin" knock-off, "Major Movie Star."

"He was just over her," a Mayer buddy fails to sugarcoat to Us Weekly. "He wasn't into her anymore. He was ready to move on."

When contacted about the split chatter, Simpson's rep told MSN.com, "I'm not commenting on her personal life."

Mayer, for his part, didn't seem too broken up about things when he hit New York hotspot, Stereo, Thursday night. According to People, he was quaffing Jack Daniels and hanging with pals.

But is there a chance the dark-haired pair, who were arm-in-arm at the Costume Institute Gala in New York City last week, could reconcile?

"They talk to each other at least six times a day," the insider shares with the magazine. "I don't know if this breakup is permanent, but for right now they are broken up."

Another mole, however, is convinced they've taken a one-way trip to Splitsville, pragmatically explaining, "She's kind and sweet and he's a terrific guy, but it's safe to say it has run its course."

News of the bust-up comes on the heels of rapturous comments made about Mayer by Simpson's dad Joe, who circuitously proclaimed his affection for the singer-songwriter to People: "If Jessica is in love, I love the things she is in love with."

Joe then tempted fate when he talked about his high hopes for the toothy twosome.

"I think the beautiful thing is that [he and Jessica] don't do the same thing. He's a legend already," gushed Simpson's not-at-all-hyperbole-prone pop. "There is no competition. He's a guitarist; that's his thing. Jessica is a singer. She doesn't play guitar, so there's no competition."

Still, there were signs that the chin-dimpled duo might not be a perfect match.

When Simpson tagged along on the Australian leg of Mayer's tour last month, they seemed to diverge on their intellectual pursuits, even as they engaged in plenty of paparazzi-captured PDA.

A mole on one of their flights Down Under told the Gold Coast Bulletin, "He was reading a book and she looked bored."

Their Australian schmoopiness capped off months of increasingly lovey-dovey behavior in the public eye.

They reignited long-simmering romance rumors by affectionately ringing in the New Year together in New York, and a month later at the Grammys, Mayer responded to Ryan Seacrest's queries about Simpson by saying (in Japanese), "She's a lovely woman and I'm glad to be with her."

A romantic getaway to Rome followed in March.

But, a Simpson source tells Us, "The same sense of excitement and interest just isn't there as much," adding, "I have no sense of a tearful breakup or anything like that. It's just losing steam. It is more of a separation."

Echoes another insider, "The truth is we won't really know if it is done for good until he goes on tour [June 1] and we see if she is there with him again. That is when we will know if this is definitive."

Next: Date & Switch: Diaz, Justin, Biel, Scarlett