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We knew that Valentine's Day date to a McDonald's drive-through was a bad sign. E! News reports that Britney Spears and her agent-boyfriend, Jason Trawick, are kaput after a year or so of on-off coupledom.

"They were fighting a lot," tattles an insider, "and have not been getting along."

The fickle flames, whose romance was alternately dogged by engagement and breakup rumors, apparently went their separate ways at the end of February, which just happens to coincide with Brit-Brit's most recent switch from brunette to blonde.

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On Feb. 26, the still under-parental-supervision popster, whose tangled, mangled locks are often said to be a reflection of her mood (a lighter coif means she's happy; a darker one means she's not), ducked into a Los Angeles salon to have her extensions brightened and brushed out.

It was a rare trip without Trawick, who not only tagged along on her successful Circus tour but in recent months has been snapped accompanying her on her frequent runs to Target and Starbucks.

He also helped her celebrate her 28th birthday in December, joined her at the Grammys in January, and jetted off on several family vacations with her and her sons, Sean Preston, 4, and Jayden James, 3.

But all that togetherness may have taken a toll.

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"They both just needed to take a break from each other," adds the source. "It wasn't working out."

This isn't the first time the pair has supposedly called time on their personal, if not their professional, relationship.

According to E!, they also "cooled off" over the holidays. And back in August, they reportedly decided to keep things "casual."

"It's a very superficial relationship," a source told ABC News at the time. "But that's admittedly exactly what she needs right now. They are not 'in love.' She loves his friendship and the fact that he takes charge. He's just what she likes in a man: one who gives his time and sacrifices his needs for hers."

This latest bust-up report is going to come as a blow to Britney's mom, Lynne, who believed Jason would make a "dream husband" (what, Kevin Federline and his baggy pants didn't fit the bill?).

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"Lynne said, 'He's the kind of man you would dream of your daughter marrying,'" a spy told Us Weekly in October. "'The kids love him, and he's stable.' Most everyone else abandoned her, but Jason refused to be completely cut out of Britney's life. He's very protective of her."

But it looks like Trawick, 38, who stuck by Spears during her head-shaving, child custody-losing, psych-ward-inclusive meltdown period, won't have to worry about losing a valuable client. E! says he remains Brit's agent. What's more, opines the source, a reunion is still a possibility.

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