Businessman Jason Rohde blamed himself for his wife's death on Monday, saying that his affair with Jolene Alterskye destroyed her and their family.
"My conduct has ripped my family apart. It has devastated my family and I know, if it wasn't for my disgusting behaviour, Susan would still be alive today," he testified in the Western Cape High Court.
He was the first defence witness in his trial, in which he is accused of his wife's murder.
Susan was found hanging from a hook behind their bathroom door at Spier Hotel in 2016.
Although her death was thought to be a suicide, her husband was later charged for her murder and accused of staging her suicide.
He has pleaded not guilty to the charges.
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Rohde took the court through his and Susan's 23-year marriage and said it was good overall.
"We had our ups and downs like any marriage would have. We could get into some awful verbal altercations. We were both to blame. Never once did I physically attack, strike or strangle my wife ever."
Affair
Jason first met Alterskye in 2013. At a work dinner two years later, he realised he was physically attracted to her.
At the end of 2015, he invited her out for a drink while he was in Cape Town.
Their relationship developed into a physical, intimate one, he said.
They would meet up in different locations and he would make a lot of excuses to fly to Cape Town so he could see her.
He did not think Susan knew about the affair, because she would have confronted him.
Their relationship continued until February 27, 2016, when Susan discovered a Valentine's card that Jolene had secretly put in his luggage.
"Susan confronted me with the card while I was in the study. My initial reaction was shock and [I was] scared. I tried to deny it and said it was an anonymous card that I got. After 30 minutes, I realised there was no point in denying it because I had been caught."
'Absolutely berserk'
Rohde says his wife went "absolutely berserk" and could not believe he would do something like that after so many years together.
They locked themselves in the bathroom and she made him call Jolene to end the affair.
Jolene wrote a 3-4 page letter and sent it to him. His wife made notes on the letter with questions that she had.
She also made him keep a copy of the letter so he could be reminded of his "dishonest" behaviour, he said.
"It (the affair) absolutely consumed Susan. She wouldn't sleep. She wouldn't eat. She would go back into my diary and I would have to explain everything to her," he said.
"She would phone me five to 15 times a day. When I got home, I would have to give my phone to her."
Every day started and ended with talking about Jolene, he said.
Rohde 'felt himself withdrawing' from Susan
Shortly after discovering the affair, Susan flew to Cape Town to confront Jolene.
She did not end up doing so but visited all the places her husband and Jolene had visited.
She took photos and sent them to him.
"She (Susan) just couldn't get her head around how deceitful I had been to her."
He said the more intense Susan became, the more he felt himself pulling away.
"I knew I should be embracing her, but felt myself withdrawing, being emotionally distant from her."
The trial continues.