Fifty-five-year-old Bobby Lee Komrowski of White Haven pleaded guilty in 2009 to third-degree murder in the death of 31-year-old Amy Comly.
Prosecutors said he killed the victim in their home in October 2007 hours after he was served with a protection-from-abuse order.
Komrowski was sentenced to 20 to 40 years in state prison but later tried unsuccessfully to withdraw the plea and go to trial.
He acknowledged in a hearing last summer that he stabbed the victim but said she stabbed him first, and he said ineffective counsel prompted his guilty plea.
Judge Joseph Augello rejected the appeal Thursday, saying Komrowski was making contradictory statements.