Byrne said his wife was "burned" and told the operator: "The stove was on and the frying pan's on the other side of the room. She's not breathing."
When paramedics arrived Byrne told them his wife had been making him a bacon sandwich and when he returned home she was dead, the court heard.
Mr Jackson said Byrne told police he had been out walking his dog for 40 minutes, but CCTV footage showed he was out for much longer than that.
Byrne was initially treated as a "grieving husband and an important witness" and said he went out for dinner with his wife the night before, the court heard.
"He said the following morning they had a lie in, he watched Football Focus then had taken the dog for a walk while she made him a BLT sandwich which was his favourite," Mr Jackson said.
Byrne said his wife was dead when he returned, the court heard.
"He never once mentioned his affair with Deborah Houlihan or his messages to her on that Saturday," said Mr Jackson.
He said Byrne's "calculated charade" resulted in sympathy from family and friends.
"It was not long before the police investigation began to unravel that charade," he said. "They obtained the CCTV footage.
"There was no evidence of any break-in that might have suggested an intruder could have broken in and been responsible."
A post-mortem examination identified white spirit on Mrs Byrne's clothing and a half-empty bottle of white spirit was found in the garage, the jury heard.
Byrne was arrested on February 15.
Married Deborah Houlihan told jurors she began an affair with Byrne after first meeting him as a patient in April 2015.
"Obviously deep down in my heart I knew it was wrong, but it felt good and I felt excited by the spark we had between us," she said.
They had sex at hotels but the mother ended the "fling" after she received a text message and a voicemail message from Mrs Byrne threatening to "ruin" her marriage.
However the affair resumed after Byrne bought a pay-as-you-go mobile phone that he kept at his office, the court heard.
Byrne was later made redundant for reasons not connected to the affair.
The trial continues.