Britney Spears and Jason Trawick
01/12/2013 AT 08:00 PM EST
01/12/2013 AT 04:00 PM EST
and Jason Trawick mutually ended their engagement
Friday, just over a year after he popped the question
to the pop star in Las Vegas.
So what was behind the pair's decision to call off their engagement? According to a close source, Spears, 31, and Trawick, 41, both wanted "different things."
"There was no third party involved," says the source of the couple, who began dating in 2009
. "Things haven't been ideal in their relationship for some time. There was a lot to work on before they could move forward and get married."
One of those things may have been Trawick's desire to maintain a life outside their relationship.
"Britney had a lot of issues with Jason doing his own thing – in business and seeing his friends," another source says. "In her perfect world he would have been home with her twenty-four/seven, so that was a point of contention; something they were always working on."
Another source of tension? Kids. "Britney wants to grow her family," says a source close to the couple. "Jason loves her boys but he is not in a place to have his own."
Though Spears recently purchased
an $8.5 million mansion in L.A.'s Thousand Oaks neighborhood to live in with Trawick and her sons Sean, 7, and Jayden, 6, another source says everything wasn't picture perfect. "They've been spending a lot of time apart in the last few months," says the source.
While the pair's relationship had become "frustrating," according to the close source, they've put up a united front. Spears told PEOPLE exclusively in a statement Friday that she and Trawick are committed to remaining "great friends."
After hearing news of the split, a source who saw the couple and her children in recent weeks says, "They both seemed happy. Especially Britney, I could tell that she was in a really great place. She smiled a lot. They were both really at ease with the boys."
As Spears ends her relationship with Trawick – he also resigned as co-conservator
over her person, which gave him authority to make decisions about her general well-being – the singer and former X Factor
judge will return to doing what she loves: music.
"It's time for me to get back in the studio," she said in a statement
Friday. "Watching [The X Factor
contestants] all do their thing up on that stage every week made me miss performing so much! I can't wait to get back out there and do what I love most."
Reporting by JENNIFER GARCIA, RAHA LEWIS and AILI NAHAS