How Avril Lavigne and Chad Kroeger Are Breaking Their Self-Imposed 'Marriage Rules'

Chad Kroeger and Avril Lavigne

Aaron Davidson/WireImage

09/20/2014 AT 09:30 AM EDT

What a difference a year makes.

They've only been married for a little over a year, but rumors are swirling that Avril Lavigne and Chad Kroeger are headed for a split – and if the lack of devotion to their own marriage rules is any indication, it just might be true.

On Thursday the Canadian pop star was seen out at Hollywood restaurant Dan Tana's, having the second girls' night out without her ring in a month. "She was sipping on white wine, and seemed to be okay," a source tells PEOPLE. "But she was on her phone a lot." On Aug. 29, Lavigne was also seen out partying at the Chateau Marmont with her girlfriends, again without her wedding band.

But in November last year, Lavigne, 29, and Kroeger, 39, told PEOPLE that they had a rule where they would not drink without each other.

"Ever," said the Nickelback frontman. "Even if we're apart for weeks." They also weren't supposed to go to nightclubs without each other. "We don't want to go anywhere that you're asking for trouble," Kroeger explained, while Lavigne added that it was just the responsible thing to do. "We want to protect what we have," she said.

They've also blatantly broken their rule about maximizing time with each other. "We don't spend more than two weeks apart," Lavigne told PEOPLE at the time. And yet, the couple haven't been spotted together since late April, when they were seen shopping in Hollywood before Lavigne headed off to South America for a tour – on which Kroeger did not join her.

The pair, who met in the studio when Kroeger was working on Lavigne's last album, had a whirlwind romance that led to an engagement after just a month and six days of dating.

"We bonded like crazy," Lavigne told PEOPLE of their instant union. "It was like we'd known each other forever." A year later, they threw a blowout wedding at a castle in the South of France.

Divorce was never going to be in the cards, according to Lavigne. "We don't like the 'D' word," she told PEOPLE last November.

• Reporting by ABBY STERN