This story contains references to domestic violence.
The woman at the centre of domestic violence allegations against war hero Ben Roberts-Smith has told a court she was threatened by a stranger on a beach who had photos of the pair having sex.
Codenamed Person 17, the woman was in a relationship with Mr Roberts-Smith in 2017 and 2018 while they were both married to other people.
She has been called as a witness during defamation proceedings launched by Mr Roberts-Smith, after several newspapers reported he had assaulted the woman.
The Age, The Sydney Morning Herald and The Canberra Times also reported claims he committed war crimes in Afghanistan between 2006 and 2012.
The 43-year-old denies all the allegations.
Ben Roberts-Smith claims a judge made critical errors in his findings about war crimes. Source: AAP / Dan Himbrechts
On Wednesday, she told the court that days before the pair were due to meet one last time, after agreeing to break up, a man confronted her at a beach near her house.
She said he had two images in an envelope showing her having sex with Mr Roberts-Smith in a hotel room, and gave her an ultimatum to tell Mr Roberts-Smith's wife or they would become public.
Within days, the woman visited Mr Roberts-Smith's house and told his wife about the affair, but says she did so to put a final stop to it.
She said she did not tell Mr Roberts-Smith about the man at the time because it crossed her mind that he might be involved.
Mr Roberts-Smith's barrister Bruce McClintock argued his client had no interest in the photos becoming public or his wife finding out about the affair.
He accused Person 17 of making up her evidence, asking her how she thought the photos she described - taken through the window of their room on at least the 20th floor of the hotel - could have been taken.
"By drone?" he said.
"It really is just a ridiculous story, isn't it?"
There was no man on the beach and she had told Mr Roberts-Smith's now-estranged wife out of spite, he said.
"What you really wanted was to end my client's marriage so you could have him for yourself.
"It was either that or just a straight-out act of vindictive revenge."
Person 17 repeatedly denied this.
Mr McClintock also accused the woman of inventing her allegations of domestic violence.
She previously told the court Mr Roberts-Smith assaulted her after they returned from a function in Canberra where she had become drunk and "embarrassed" herself.
When they entered their hotel room, she says he took her by the shoulders, began shaking her, and punched her in the eye.
Mr McClintock suggested to Person 17 what actually happened is that she had sustained a black eye earlier that night when she "bashed" her head on stairs during a drunken fall.
If he had actually hit her, she wouldn't have agreed to meet Mr Roberts-Smith again about a week later, Mr McClintock said.
"It is not a good indication of fear, is it, if you want to replicate the very situation where the incident that you say happened had occurred?" he asked.
She responded: "I was simultaneously in love with him and afraid of him."
Person 17 also told the court she had in 2018 contacted one of the journalists now being sued to learn whether she would be outed in their coverage of Mr Roberts-Smith.
She told Nick McKenzie about the alleged assault, and he organised for her to speak to federal police, she said.
Person 17 said she ultimately decided not to go through with the complaint, largely because she was scared Mr Roberts-Smith would seek payback.
The trial continues.
If you or someone you know is impacted by family and domestic violence, call 1800RESPECT on 1800 737 732 or visit 1800RESPECT.org.au. In an emergency, call 000.
