A lot of people assumed that John Mayer “dumped” Jennifer Aniston, not the other way around, probably because she’s always portrayed as such a sad sack and a hanger-on by the media. A journalist at the Chicago Sun Times claims to have a very solid source who says that it was Aniston who did the dumping, not Mayer, and that she just got fed up with his cheating. Mayer was photographed in a hot tub in Mexico last week with a woman who wasn’t Aniston at a time when the actress was back in LA. The woman turned out to be a wife of one of his band members and not a fling, but the damage to his already playboy image was done. What’s more is that Mayer is said to have cheated on Aniston with three different women: a groupie, a promoter’s assistant, and a cocktail waitress, not necessarily in that order or at the same time.

Much is being made about John Mayer allegedly dumping Jennifer Aniston, but one of my best Hollywood sources — super-close to both Aniston and her best pals Courtney Cox and David Arquette — insists it was the ex-“Friends” star who gave Mayer his walking papers.

It was “Jen who decided to move on,” says the friend. “She is very fond of John and has thought he might be the one. She finds him funny, sexy and very talented. … Plus he understands all the aspects of living in a fishbowl. But in the final analysis, she just got tired of his roving eye.”

A vivid example can be seen in the new Us Weekly (hitting newsstands this week), which has photos of the singer frolicking in a hot tub in Cabo San Lucas, Mexico, on a trip without Aniston.

Apparently, Aniston gave Mayer a “three strikes and you’re out” ultimatum — after learning about his “quickie” flings with a cocktail waitress and a promoter’s assistant for his concert tour.

That was two strikes. Another dalliance, with a groupie, was the final straw for Aniston.

A longtime major Hollywood studio exec — and good Aniston buddy — adds this: “Above everything else, Jennifer is looking for stability and loyalty in a relationship. She still is hurting from losing Brad [Pitt] to Angelina [Jolie] — even after all this time.”

[From The Chicago Sun Times]

If all this is true, I can’t believe Jen gave him first one chance, then another one after she realized he was sleeping around on her. Maybe she wanted to keep it casual but in that case she should have let him go on tour alone and kept her distance. Hindsight is 20/20 though, and who knows what their relationship was like. I’m not judging her, more like giving a girl unsolicited dating advice that she probably could have learned from that movie she’s producing and starring in, “He’s just not that into you.”

This is the guy who bragged that his penis had a great batting average, so it’s not like he’s the faithful type.

Meanwhile Aniston is finding love – or at least temporary lust – in the arms of a guy who seems like he might be a smidgen more commitment-minded than Mayer. She’s said to be dating Selma Blair’s on-off ex, a model named Matt Felker. Go Jen!