A man who denies jointly murdering his wife by asking his mistress to stab her to death, has been giving evidence at Swansea Crown Court.
Stephen Marsh said his relationship with Harris was a bit of fun
Stephen Marsh of Gorseinon, said he was at a friend's house the night his lover Rebecca Harris, 30, crept into the marital home murdered his wife Jaspal.
Taking the stand for the first time, he said he had been "stupid" to have had several affairs and had loved his wife.
"I loved her to bits. We just always wanted to be together," he said.
Rebecca Harris had admitted the murder of Jaspal Marsh, 36, last July. The court has already heard how she suffered 30 knife wounds after Harris attacked her in her bedroom with a kitchen knife.
The prosecution alleged Mr Marsh established an alibi by going drinking with a friend in a city centre pub and set the murder scene by ensuring his wife left their home unlocked before going to bed.
On the evening of her death, the court heard how Mr Marsh had arranged to spend the evening with a former lover Natalie Yemm.
But when Miss Yemm called off the arrangement he sent a text to another former lover, Julie Owens, asking if he could spend the night with her.
When she declined he contacted a friend who allowed him to "crash on the settee" at his flat in the centre of Swansea.
Huw Davies QC, prosecuting, asked Mr Marsh whether he had been "desperate" not to go home to Gorseinon because he knew Natalie Harris, planned to enter his home and kill his wife.
Under cross examination, Mr Marsh said he simply wanted a good night out and the text to Miss Owens had been sent in error.
In his evidence Mr Marsh said his marriage had become difficult because of their work commitments.
Jaspal Marsh was stabbed more than 30 times in her bedroom
His affair with Harris - a married mother -of-one - began when they worked together at a directory inquiries call centre in Swansea and he described it as "a bit of fun".
"It was fun, it was a distraction in working hours," he said. "That's all it was ever regarded as. Nobody could replace Jas.
"I explained to her (Harris) it was for fun and if she ever wanted anything more than that I was the wrong person to be with.
"I'm ashamed of myself - Jas did not deserve anything like that," he told the jury.
"I was immature and I accepted the attention with glee
"The affairs I had were stupid and should never have happened."
He said in the months leading up to his wife's death Harris was trying to spend more and more time with him.
"She'd been quite claustrophobic for a number of months. She wanted to be there all the time," he said.
Mr Marsh said on the night of the murder he had met up with a friend in the Potters Wheel pub and had gone back to his friend's house, where he played a football game on a PlayStation until he went to sleep at 2am.
Harris claims Marsh had "pestered" her to kill his wife
He said during this period, he exchanged text messages with Harris, but could not remember their content.
Mr Marsh also told the court he was an alcoholic in denial and had struggled with the problem for years.
He said he drank four cans of cider before starting work every morning and would drink up to 14 cans a day, every day.
He said the alcohol would give him confidence and made him "more bubbly" at work but also tended to affect his short-term memory.
But he said at no time did he encourage Harris to kill his wife or was he aware that that was what she was doing.
He said it was not until he finished work the following day that he returned to his home in Gorseinon.
Mr Marsh said he discovered her body lying on the floor in the bedroom.
"It was a little unreal - I can't explain what I was feeling, it did not register."
Mr Marsh said he did not suspect Harris had killed his wife and it was only when the police handed him a copy of her confession that he believed for certain she had.
Asked what he now thought of Harris, he said: "I've got no thoughts or opinion of Rebecca. I can never understand why she did it - I just try to block her out of my mind."
The trial has previously heard Harris carried out the killing eight months after she begun a sadomasochistic relationship with Mr Marsh.
She insisted Mr Marsh persuaded her to carry out the crime, saying he wanted his wife "out of the way" and on the night of the murder he sent her text urging: "Do it, just do it."
The trial continues.