George Clooney, Elisabetta Canalis "Bickering" Nonstop Pre-Split

USMagazine, Thursday, June 23, 2011, 6:59am (PDT)

What went wrong with George Clooney and Elisabetta Canalis?

After two years together, the couple announced their breakup to Us Weekly and the world on Wednesday.

PHOTOS: George and Elisabetta, the way they were

A Clooney insider told Us there were major signs of trouble for the actor, 50, and Italian model, 32, during their New Year's getaway in Mexico.

"She drove him nuts," the source says, explaining there was "non-stop bickering over little things...He would only hang out with his friends, and more or less left her to herself and her friends."

PHOTOS: Who else has George dated?

Clooney, who's had very few long-term relationships in his life, had been "creating distance" for many months, the source added. His excuse at the time? "Work. [He] was knee-deep in pre-production on a couple projects."

One of those projects was Gravity; he and costar Sandra Bullock are reportedly wrapping up that thriller in London.

PHOTOS: Stars who've dated models

Clooney famously swore off remarrying, telling Piers Morgan in January that he wouldn't walk down the aisle again after his failed union with actress Talia Balsam in the early 90s. Italian model Canalis however, seemed more invested in the institution. "I am a firm believer in marriage," she said in a June interview with Italian magazine Chi. "In the future I will be married, but for the time being I am happy as I am."

Get more Us! Follow us on Twitter, Friend us on Facebook, Subscribe to Us Weekly