Former Hills star Jenner and singer Lavigne have called time on their relationship after almost two years together, it was announced in January.
Entertainment magazine Life & Style reports that a source confirmed the break-up, saying it was down to opposing views on marriage.
Avril, 27, was previously married to Sum 41 singer Deryck Whibley and reportedly wanted to go down the aisle again - this time with 28-year-old Brody.
Could Jenner have been put off marriage by his step-sister Kim Kardashian's recent failed union?
22,000 people agreed to clean toilets for WiFi because they did not read the terms.
Tools designed to ensure computer code in smart cars does not crash has been inspired by hungry penguins.
The rounded sleeping capsules send guests drifting into ocean before arriving on desert island by morning.
Sitting on the saddle activates the part of the brain responsible for learning, a study has claimed.
Scientists are appealing for more people to donate their brains for research after they die.
Life on Earth may have arrived from Mars on an asteroid, scientists have claimed.
Lunar mission scheduled at the end of 2017 could find out if beer can be brewed on the moon.
A bottle used to teach children how far litter can travel ended up on Scottish beach after 8,700-mile journey.