Balthazar Getty: Yes, My Wife and I Have Separated

07/21/2008 at 07:05 PM EDT

Balthazar Getty, who has been photographed smooching actress Sienna Miller, has announced that he's splitting from his wife Rosetta Getty, with whom he has four children.

"The breakdown of a marriage is a very difficult and painful experience especially when children are involved," he said in a statement released Monday. "In light of the fact that many pictures have surfaced in print and on the Internet which has caused myself and my family great embarrassment, I felt it necessary to at least acknowledge publicly that yes indeed my wife and I have separated and I will not be commenting any further."

The Brothers & Sisters actor, 33, was recently seen with Miller, who was topless, in a boat off the Amalfi coast.

A friend told PEOPLE that Getty's wife is upset by the public affair. "It's humiliating," a friend said. "Rosetta left the country to protect the kids, and he continues to see Sienna publicly."