He will serve a sentence of life in prison without the possibility of parole.
The family of the victim, 29-year-old Lauren Phelps, were present in the courtroom to provide a victim impact statement.
An autopsy report revealed Lauren had been stabbed 123 times.
The report stated she died from multiple stab wounds to her face, neck, torso, arms, and jugular vein.
Stay on top of breaking news stories with the ABC11 News App
Officials said when they found the victim, on Sept. 1, 2017, she was in the fetal position on her bedroom floor.
She was taken to the hospital, where she later died.
Phelps, 29, claims he was on cold medicine at the time and doesn't remember what happened.
"I have blood all over me and there's a bloody knife on the bed, and I think I did it. I can't believe this," he said during a 911 call.
Raleigh man accused of stabbing wife: 'There's a bloody knife on the bed, and I think I did it'
Autopsy: Wife stabbed 123 times in Raleigh cold medicine murder
UNC professor: It's 'plausible' too much cold medicine caused Raleigh man to kill his wife
Raleigh man who said he thought he killed wife after taking medicine appears in court
In that 911 call, Phelps claimed he had a dream that he killed his wife. When he woke, he found himself covered in blood, with Lauren's body on the floor.
Warrants released in April showed relatives revealed the couple had money issues.
Detectives poured over social media, revealing Phelps may have been "possibly fascinated with and mimicked a portrayed serial killer character from the movie American Psycho."