The night of Jan. 23, Ashton Kutcher wasn't with estranged wife Demi Moore at the Beverly Hills home they once shared. As Moore, 49, collapsed and suffered convulsions after smoking an unnamed substance (according to a frantic 911 call placed by a friend), Kutcher was thousands of miles away in Sao Paolo, Brazil -- hanging out with model Alessandra Ambrosio at bar Numero.

And now that the Two and a Half Men star, 33, is back in Los Angeles (reports have placed his car near their home), it's unclear how much a role Kutcher will play in his estranged wife's recovery, sources tell the new Us Weekly, out now.

"He just wants to move on," a Kutcher friend tells Us. "He cares about Demi and would help if asked, but he's not part of her life anymore."

Indeed, long before their November split (Kutcher cheated on her with Sara Leal, 22, in September), the Margin Call actress has been struggling with low self-esteem, an obsession with staying young and thin and acted out with partying and self-destructive behavior.

Kutcher even took a paternal role with her three daughters Rumer, Scout and Tellulah Willis, another source reveals.

"For a while, Ashton was acting as the primary parent because Demi was so out of control," another source says.