Eighty-one-year-old Rudi Koos pleaded guilty to third-degree murder in Montgomery County Court in May.
Authorities said Koos killed his 75-year-old wife, Waltraud, in their home in Souderton, where the couple had lived since emigrating from East Germany in 1957.
Defense attorney Frank Genovese said his client is remorseful. He said Koos snapped because he thought his wife of 59 years was cheating on him.
