Ben Stiller Wastin' Away in Margherita-Ville After Separation (PHOTO)

Ben Stiller apparently does what lots of people do when they have relationship trouble ... eat.

In Ben's case, he's eating the best in the world ... what appears to be a delicious Margherita pizza courtesy of a chef in Naples, Italy.

As we told you Friday, Ben and his wife of 17 years have separated. They have 2 kids. They have not filed for divorce, but based on their statement about raising their children in the future ... it seems inevitable.