And it's emerged this week that the 13-year age gap between the couple could have been to blame for Jarret's cold feet.
Friends of the sports star – who celebrated his 27th birthday last week – have said he was uncomfortable about the difference in years, reports the Daily Mail.
The paper says the couple had clashed over what they have described as the 40-year-old's "high maintenance" lifestyle too.
There were also reports that Jarret's relationship with his future stepsons - Renee, 17, and 14-year-old Liam – had become strained in recent weeks.
Rachel - the former wife of legendary singer Rod Stewart - and Jarrett were due to walk down the aisle in a lavish ceremony attended by Hollywood stars such as Michelle Pfeiffer and Sharon Stone on August 14.
The couple, who announced their engagement in August, bought a £2.2 million house in LA's Hermosa Beach together last year and had said they hoped to have a child together following the wedding.