Sydney jeweller Phillip Leung has been found guilty of killing his male partner after three trials spanning four years - a first in NSW's legal history.

Leung, 51, sobbed uncontrollably in the dock as the jury found he was guilty of manslaughter over the death of his long-term partner Mario Guzzetti - a crime for which he had previously been acquitted.

Legal first ... Philip Leung has been found guilty after three trials. Credit:Anthony Johnson

"This is wrong, just wrong," Leung said, through tears.

The trial in the NSW Supreme Court had heard that on the morning of April 7, 2007, a row erupted between the couple over a tiler's bag of cement that was obstructing access at their home in Alexandria.