A businessman accused of murdering his wife told police he thought she was just being “dramatic” when she fell fatally injured to the floor.
Mark Arthur claimed he had put his arm out to stop Heather Arthur walking past him in their study because he wanted to talk to her.
Prosecutors claim he stabbed Mrs Arthur to death after she told him their marriage was over.
Arthur has admitted manslaughter but denies murder on the grounds of loss of control and is on trial at Newcastle Crown Court.
In extensive interviews by police after his arrest, he gave what officers described as a “vague” account of what had happened in their home on Woodbine Road, Gosforth, Newcastle, last April.
But he denied having stabbed her and when asked how she had died, he said: “I don’t know exactly.”
Arthur said he had been sitting at his desk in the study of their Gosforth home when his wife came in from the kitchen.
He said: “We exchanged a few words and Heather was angry.
“I reached out to stop her walking off. She tried to barge past me, she tried pass my arm and she fell face down forwards onto the floor.
“She didn’t move, I didn’t really know what to do. I thought she was being dramatic.
“I rolled her over and that’s when I saw a lot of blood and the handle of the knife.”
Arthur said he tried to give her mouth to mouth and when it didn’t work, he paced around, sat on the stairs and went to the toilet.
He told police: “I just looked at Heather. I thought she was dead.”
Arthur, who said he had never been violent to his wife, said their marriage had its ups and downs and they had been going to Relate for counselling.
He said he remembered going to his GP surgery afterwards. Asked what he said to his doctor, he replied: “I was very very upset and confused. I thought everything was my fault.”
The interviewing police officer accused Arthur of being vague about what had happened and asked him if 50-year-old Mrs Arthur’s death was his fault.
Arthur replied: “I don’t think so. I don’t think her death is my fault.”
Asked how she died, he said: “I don’t know exactly.”
Arthur, 50, has since admitted manslaughter but denies murder on the grounds of loss of control.
The court has heard Mrs Arthur had fallen in love with the saxophonist in a jazz band she sung with and decided to leave her partner of 30 years, Mark Arthur.
Mrs Arthur, who used to work for British Airways, thought the relationship had run its course and had talked to her husband about splitting.
Jurors were told she was a talented jazz singer and had grown close to the saxophonist in the band she performed with, Paul Gowland.
One morning last April, Mrs Arthur returned to her marital home after doing the school run and popping to Sainsbury’s.
Prosecutors say she told Arthur their marriage was definitely over and he stabbed her once in the chest, piercing her heart.
After killing Mrs Arthur, Arthur went to his doctor’s surgery nearby wearing boxer shorts and a top, bursting in on his GP and saying he had hurt his wife.
When officers got to the couple’s home they found Mrs Arthur lying dead in a pool of blood in the study at the back of the house, next to her husband’s desk.
Police untied a tightly knotted scarf round her neck, revealing a knife sticking out of her chest.
The couple met at university in London and had been together for 30 years and married for around 10 years.
Witnesses have claimed Arthur, who ran an IT business, was controlling and had installed GPS tracking software on his wife’s phone so he would know where she was.
The trial continues.