A husband told a jury it was a bizarre coincidence he lost control of his car and knocked down his wife's ex-lover.
Timothy Porter admitted Ian Cowpland had made his life a living hell after claiming Porter's wife's child was his own.
However, Porter denied deliberately trying to mow him down in Battle High Street in August last year.
Porter, a sales manager, formerly of Catsfield Road, Crowhurst, near Hastings, has denied causing grievous bodily harm with intent and an alternative charge of causing actual bodily harm at a trial at Lewes Crown Court.
Mr Cowpland suffered a broken kneecap and cuts to his head and arm.
Porter, who has inflammatory bowel disease, said he must have accidentally lost control of his car when he suffered a severe and sudden stomach pain.
He told the jury he had not seen Mr Cowpland walking along the street before the accident but could not remember anything else.
He said: "It was just bizarre he was involved."
During the trial, the jury has heard how Porter's wife, Melanie, had an affair with Mr Cowpland from May 2000 until June 2001.
After the relationship ended she gave birth to a daughter, Georgina, in November 2001.
When Mr Cowpland later found out about the baby he concluded he was the father. He has started legal proceedings to resolve the issue of paternity and to gain access.
Porter told the court he had found out about the affair when Mr Cowpland rang to tell him.
He and his wife and been together for 18 years and he had forgiven her, blaming himself for her infidelity because he had been struggling to cope with his illness.
Porter said Mr Cowpland had conducted a malicious campaign to try to split up him and his wife.
Mr Cowpland had harassed them and bombarded his wife with threatening text messages.
He had called at their home and contacted the couple's friends to tell them he was Georgina's father.
His wife was too scared to leave their home and they had been forced to change their phone number. At the time of the accident, they had put their home in Crowhurst on the market because they needed to move away from Mr Cowpland.
Porter said: "He made our lives feel like the Twilight Zone.
"Everywhere we went he was there.
"He wanted to make as much trouble for Melanie and I as he could."
During cross-examination, he denied he hated Mr Cowpland and had deliberately driven at him to cause him injury.
He said he was feeling happy at the time of the accident because he had been promoted at work that day and the house was sold.
He said: "I had no reasons to do that. I had a fantastic life and a fantastic day."
He admitted the paternity issue still had to be settled.
He said: "Where she came from does not bother me.
"I love her. I am her father and always will be."
Porter has moved from Crowhurst and an order has been made preventing the publication of his address.
The trial continues.
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