Michael Barbar, 54, admitted that he strangled his wife, 43-year-old Maysam Barbar, and their 6-year-old daughter Tamara.
The two were found dead in their Perris home in the 2800 block of Banner Place Nov. 14, 2009.
Barbar testified in court that he lost control of his emotions while under the influence of alcohol and drugs. He also testified that in the months before the killings, he learned that his wife had committed adultery with at least three different men, including a 2002 affair that resulted in Tamara's birth.
A jury in Riverside found him guilty of two counts of first-degree murder after three hours of deliberations. He was also found guilty of lying in wait, which makes Barbar eligible for the death penalty. The penalty phase begins on July 30.