Britney Spears allegedly split with her fiancé Jason Trawick after disagreeing about the size of their family.

The singer has two sons Sean Preston, six and Jayden James, five, from her first marriage to Kevin Federline. It appears she was keen to increase the size of her brood.

"It was pretty obvious Britney wanted another baby," a friend revealed to British magazine Look. "Maybe Jason wasn't ready for that. But just because he and Britney can't make it work as a couple, it doesn't mean he won't be there for her as much as he can."

Jason has previously been credited for helping Britney get back on track following her breakdown in 2007. She was placed under court-supervised conservatorship, and Jason was with her every step of the way back to regaining her place in the spotlight in 2009.

Following the demise of their relationship, the 31-year-old star is said to be struggling to cope on her own. Not only has she faced personal heartache in recent weeks, but the singer has also left TV talent show The X Factor US after one season.

"The X Factor really took its toll," a source divulged. "Especially when critics were so mean about her. The rumours she had to quit before she was pushed must have made everything worse - I guess she took it out on Jason."