Jessica Simpson's John Mayer texts blew up Romo

Jessica Simpson's boyfriend dumped her after he found text messages from her ex-lover. US Entertainer Jessica Simpson. Jessica Simpson's boyfriend Tony Romo dumped her after he found text messages from her ex-lover John Mayer. EPA/MATTHEW CAVANAUGH

US Entertainer Jessica Simpson. Jessica Simpson's boyfriend Tony Romo dumped her after he found text messages from her ex-lover John Mayer. EPA/MATTHEW CAVANAUGHAmerican football star Tony Romo, who split from Jessica last week, was reportedly furious when he discovered the singer-and-actress was still in touch with her former boyfriend John Mayer.When Jessica refused to explain why she had kept the messages from the musician, Tony decided to end their 20-month relationship on the eve of her 29th birthday.A source told gossip website RadarOnline: "They were hanging out and he picked up her phone and she got defensive about it. Tony found messages from John and went ballistic."Tony dumped her right then. He walked out and that was it."Jessica was so devastated by the split she cancelled her Barbie and Ken-themed birthday party last Friday (10.07.09).A source said: "Jessica was too heartbroken to have a big bash. She knows that she and Tony are broken up for good. They were heading in different directions."Since the break-up, Tony has been seen partying with friends at Los Angeles nightspots MyHouse and the Key Club.It has been claimed Jessica's father-and-manager Joe Simpson added to the increasing strain on their relationship.Joe's constant involvement in his daughter's personal life reportedly became too much for Tony to handle.