Britney Spears is worried her boyfriend isn't "mature" enough for her.

The 32-year-old pop star started dating David Lucado two months after splitting from her ex-fiance and former manager Jason Trawick, but now the relationship is approaching the one-year mark, Britney is reportedly having second thoughts.

"Britney has been have doubts since before Christmas. She really fell for David at the start of the romance, but now she feels she jumped into things too quickly after splitting from Jason. She was so desperate to have someone by her side. Britney's worried he's not mature enough for her - she's used to being spoiled by her boyfriends but, with David, she's been joking to friends that he's like a third son," a source said.

The 32-year-old star - who has sons Sean Preston, eight, and Jayden James, seven, from her marriage to Kevin Federline - is allegedly not ready to get hitched to David, 27, and wants to focus on her concert residency in Las Vegas.

"Britney's really torn because she still likes David, but she doesn't see their relationship ending up in marriage. She was so relieved he didn't propose at Christmas after hearing from friends he was keen to pop the question. She starts her next stint of concerts in Vegas in February, so she doesn't want to rock the boat. But she's feeling the romance has lost its spark and she doesn't want to string him along if there's no future," the insider added.