Kate Walsh: ‘Private’ Time With Co-Star?

News last week of Kate Walsh’s separation from film exec Alex Young shocked the public—at least, that portion of the public who thought a marriage entered into after just a few months of courtship was built to last.

But now the mystery behind the puzzling breakup may be unraveling.

Star magazine reports that 41-year-old Private Practice star Walsh may have been getting too chummy with 39-year-old co-star David Sutcliffe.

“Kate really likes David, and knowing that didn’t help Alex’s fragile ego,” a friend of Walsh’s tells the magazine. “Kate and David had a real connection playing lovers on the show, and she didn’t seem to have that with her own husband.”

Canadian actor Sutcliffe, who plays cop/love interest Kevin Nelson, divorced former Growing Pains actress and Playboy Playmate Julie McCullough in 2003.

News broke last week that Young had filed for divorce from Walsh, citing irreconcilable differences.  The filing disclosed that the two had been separated since November 22.

Walsh and Young married in December 2007, after a dating for a few months.