Rocker Avril Lavigne‘s marriage headed for trouble.

The "Complicated" singer’s two-year union to Sum 41 rocker Deryck Whibley is in turmoil as a result of his manic bar hopping and seemingly bachelor-like behavior, say sources.

Recently the same night Avril was performing in Lijang, China – Deryck was spotted out with a statuesque brunette beauty at Villa nightclub.

"It seemed as if Deryck and his woman couldn’t keep their hands off of each other," an eyewitness told The ENQUIRER.

The Ontario natives – who wed in July 2006 – have been virtually leading separate lives, according to the insider.

The two have tried relying on long-distance phone calls and e-mailing to hold their troubled relationship together. But while Avril has been touring the world, Deryck has back-burnered his career in favor of partying, say sources.

"Deryck isn’t motivated in his own career, so he’s been drinking and partying," charged the insider.

On Aug. 25, Deryck and some pals hit L.A.’s Key Club and behaved like belligerent drunks, according to sources.

"Deryck and his friends got sloshed and then tried to pick a fight with a group of bigger guys," said the insider.

Avril was furious!

For all the details pick up the latest ENQUIRER.