Johnny Depp's legal team has accused Amber Heard of using drugs, striking him and manipulating photos she has used as evidence of his alleged abuse.
Ms Heard, 36, was being cross-examined about her allegations that Mr Depp could be violent while using alcohol and drugs.
The 58-year-old actor is suing his ex-wife for $50m (£40m) for a column she wrote in which she claimed to be a victim of domestic abuse.
He has denied ever assaulting her.
Mr Depp's lawyers cross-examined Ms Heard on her version of events related to a lengthy 2015 argument between the former couple, which took place while in Australia.
That argument has been raised repeatedly over the course of the trial.
Mr Depp has claimed his ex-wife severed his fingertip by throwing a vodka bottle at him. Ms Heard has told jurors that Mr Depp sexually violated her with a bottle.
In court on Tuesday, Mr Depp's lawyer questioned why Ms Heard did not seek medical attention despite claiming she suffered cuts and bruises during the chaotic fight.
"You're the one who assaulted someone with a bottle in Australia, isn't that right Ms Heard," attorney Camille Vasquez said.
In response, Ms Heard said that she "didn't assault Johnny, ever".
But she did acknowledge that she struck Mr Depp on several instances, which she said happened after "years of not defending myself". She made similar statements on Monday, saying she "reactively" hit him during physical altercations.
Jurors were also shown an extract from a journal - which Ms Heard described as "love notes" - in which she appears to have apologised to Mr Depp.
"I'm sorry I can get crazy. I'm sorry I hurt you," she wrote. "I can get wicked when I'm hurt".
Explaining the entry, Ms Heard said that "it's important to apologise when you're trying to move past fights".
Jurors also heard audio in which Ms Heard can be telling her then husband that "she gets so mad, she loses it" and that she can't promise "she won't get physical".
Ms Vasquez also questioned the veracity of a May 2016 photograph that Ms Heard has said shows the aftermath of Mr Depp's alleged physical abuse.
"Isn't it true you just edited these photographs?" Ms Vasquez said.
Ms Heard replied: "No, I've never edited a photograph."
During the gruelling cross-examination, jurors were also shown an itinerary for the couple's wedding, which included plans for a "dance party and drugs and music".
Ms Heard has repeatedly characterised Mr Depp's drug use as problematic and a source of tension in their marriage.
"So, your original idea was to do drugs on an island after your rehearsal dinner to the drug-fueled monster that you were about to marry?" Ms Vasquez asked.
In response, Ms Heard said it was a draft itinerary and that there was "going to be weed" at the event. She also admitted to drug use on her 30th birthday.
Over several days of testimony earlier this month, Ms Heard repeatedly said that Mr Depp had attempted to control her career, did not like her taking on new roles, and sometimes became jealous of her co-stars.
During cross-examination, Ms Vasquez accused Ms Heard of being the "jealous one", who had landed her role in the high-profile Aquaman film thanks to Mr Depp.
"No, Ms Vasquez, I got that role by auditioning," she responded.
Mr Depp's defamation case against his former wife hinges on a 2018 opinion piece in the Washington Post newspaper in which she described herself as a victim of abuse, though the piece did not name Mr Depp.
She has countersued him for $100m.