He declared: 'There was no domestic violence, nor sexual violence.' Extraordinarily, he added: 'I slapped her, but I didn't abuse her.'
Arantes also told The Sun: 'There was not sustained abuse. I'm not sorry for slapping her.'
It came as Rowling suffered a major backlash over her decision to go public on her views about transgender issues, which she said was influenced by her own experience of domestic violence and a serious sexual assault as a young woman.
A parade of Harry Potter stars – who all owe their Hollywood careers to Rowling – lined up to put the boot in, rejecting her concerns about transgender issues.
The author wrote on Wednesday night that she was 'deeply concerned' some young people faced enormous pressures to switch genders.
She even claimed she might have changed to become a man herself to turn herself into the son her father openly wanted, if she had faced the influences around today when she was a girl.
Amid the fallout yesterday, a British school dropped 'J K Rowling' as a name for one of its houses because she was 'no longer felt to be an appropriate role model'.
And even Rowling's favourite Harry Potter website, The Leaky Cauldron – the biggest fan site in the world – suggested followers should stop buying her books or watching her films.
In her deeply personal and compelling 3,600-word essay posted to her website, Rowling described the dangers of young people being convinced to change their gender and then regretting it.
She savaged 'trans activists' who disagreed with her, and revealed some of the vile insults they had thrown at her for speaking her mind.
She cited one of her five reasons for going public as having suffered a 'violent marriage' to Portuguese former TV journalist Arantes, to whom she had a whirlwind marriage in the 1990s. She also said she had been the victim of a sexual assault in her twenties, but did not identify her attacker.
Yesterday, speaking at his home in Porto, northern Portugal, Arantes told the Daily Mail: 'I'm not exactly aware of what she said but I have nothing to add.
'There was no domestic violence, nor sexual violence. I don't know exactly what she said, I still have to read it, but I'm not interested in commenting or refuting.
'I don't know why she involved me, if she involved me and if she was really referring to me. Apparently it has to do with transsexuals and transphobia. I have nothing to do with that and she shouldn't involve me.'
Arantes, 52, was quoted in the past as saying he and Rowling had split up after an argument when their daughter Jessica, now 26, was a baby, saying: 'I admit I slapped her very hard in the street.'
Yesterday he insisted: 'I slapped her, but I didn't abuse her.'
Rowling made the decision to move to Porto after her mother passed away in December 1990, and met Arantes two years later.
The couple were brought together by a love of books and married in October 1992, but Rowling left with her daughter - who was only two months old at the time - in November the next year.
Rowling returned the UK and set up in Edinburgh where she would get her life-changing publishing deal.
Arantes came to find her in 1994 to see his young daughter but Rowling took out a restraining order against him. He currently lives in Porto in a townhouse owned by his mother.
Amid the fallout from Rowling's essay yesterday, Bonnie Wright, the actress who played Ginny Weasley in the Harry Potter films, joined her co-stars Daniel Radcliffe and Emma Watson in choosing to attack the creator of the roles that made them famous.
Wright, 29, tweeted from Los Angeles: 'If Harry Potter was a source of love and belonging for you, that love is infinite and there to take without judgment or question. Transwomen are Women. I see and love you, Bonnie x.'
Watson, 30, who played Hermione Granger, told her 29million Twitter followers: 'Trans people are who they say they are and deserve to live their lives without being constantly questioned or told they aren't who they say they are.'
Watson, who is a UN Women Goodwill Ambassador, wrote: 'I want my trans followers to know that I and so many other people around the world see you, respect you and love you for who you are.'
Many questioned the timing of their social media posts because they came hours after the author spoke about escaping her 'violent marriage' and also revealed she was seriously sexually assaulted as a young woman.
One Twitter user replied to Watson: 'I've never seen someone bite the hand that fed them so callously.
She just disclosed her sexual assault and this is your response. Your 'feminism' is back to front. It's a joke.' Others told Wright: 'You clearly haven't read J K's essay' and 'You would have been nothing without her. Shame on you.'
Warner Bros, the Hollywood studio behind the blockbuster Harry Potter films, issued a carefully-worded statement praising 'the work of our storytellers who give so much of themselves' while calling for 'understanding of all communities and all people'.
The Weald School in Billingshurst, West Sussex, wrote to parents announcing that it was scrapping plans to use J K Rowling's name because she was 'no longer felt to be an appropriate role model'.
Deputy headteacher Sarah Edwards said: 'J K Rowling has tweeted some messages which are considered to be offensive to the LGBT+ community (specifically, transphobic) and we feel that we do not wish to be associated with these views.'
Instead the house will be named Blackman, after children's author Malorie Blackman.
However, support for Rowling came from thousands of tweets and messages backing her views that young people may regret changing gender if they are rushed into it.
Gingerbread, a charity supporting single parents which Rowling has long championed, said: 'We remain grateful for her patronage.'
