Oh, snap! I hope at least part of this true just because it’s such good gossip. According to one of Radar’s sources, Tony Romo dumped Jessica Simpson after he found messages from John Mayer on her phone. Apparently the idea of Jessica “cheating” on him with Mayer was enough to send Romo into some kind of angry, disgusted tailspin and he “dumped her right then. He walked out and that was it.”

If I remember correctly, Mayer and Simpson had broken up just a few months before she met Tony. The shared Simpson-Mayer history is a little sketchy – at times, Mayer has gone out of his way to defend Jessica, and yet at other times it seems like he was a real bastard to her. John Mayer alone is enough self-perpetuating drama, but add in some confusion with Jessica and Tony, and this is juicy:

Dumping someone before their birthday weekend seems especially harsh, but a source tells RadarOnline.com exclusively that Tony Romo had good reason for calling it quits with Jessica Simpson the night before her Barbie and Ken-themed bash. He found messages from her ex John Mayer!

Flying into Los Angeles on Thursday, Romo quickly made up for lost time with Simpson but their reunion quickly took a turn for the worse. “They were hanging out and he picked up her phone and she got defensive about it,” the source revealed. “Tony found messages from John and went ballistic.”

While the couple has had their fair share of rocky patches during their relationship, the idea of Simpson possibly cheating with Mayer was the straw that broke the camel’s back: “Tony dumped her right then. He walked out and that was it.”

Since them, Romo has been taking comfort in his group of guy pals who are in town with him while he films a Pepsi commercial and attends the ESPYS on Wednesday. Since the breakup, he and his crew have been spotted all around town from club MyHouse to dinner at Yamashiro to partying at the Key Club.

[From Radar]

It’s perfectly possible that Jessica and Mayer are still on speaking terms, to the point were they text message or talk on the phone occasionally. I’m not sure that I buy that Jessica was “cheating” on Romo with Mayer – or are we considering texting (or sexting) cheating at this point? I suppose it depends on what Jessica and Mayer were saying to each other. Mayer seems like a good candidate for phone sex (especially if he’s paying with a credit card), but I don’t see Jessica doing that. My guess is that Jessica and John still have some kind of friendship, and that it totally annoyed Tony, but that probably wasn’t why he broke up with her. I think Tony was just looking for a way out.

Thus far, the gossip surrounding the split hasn’t been too bad – probably because Jessica hasn’t really talked about it yet. When she gives her first post-split interview, I have a feeling it might get dirty. Not sexy dirty, either. Bad needy/clingy/crazy dirty. Meanwhile, various gossip sites are running comments from people in the Romo-Simpson orbit. I liked this one, from one of Tony’s Cowboy teammates, Ken Hamlin. Ken claims he’s “shocked” with the split, but continues “there is a reason for everything, and you never know what is going to happen. His personal life is his personal life. [Jessica] was a good person and a good friend. I didn’t give her no flack. Every time I met her, I had nothing negative to say about her. She did a good job.” Dude, Jessica didn’t die. She just got dumped. What’s with all of the memorializing?

Here’s Jessica and Tony out in Dallas on May 26th. Images thanks to Fame.

Jessica Simpson and Tony Romo are shown out in Dallas on 5/26/08. Credit: Fame