Amber Heard did not tell her mother that Johnny Depp was abusive towards her because she did not want her violent father to know, a court has heard.
Heard described the Hollywood star as a Dr Jekyll and Mr Hyde character who was breaking her heart.
The Aquaman actress was completing her evidence in Depp's High Court libel case against The Sun over allegations of domestic violence.
Heard, 34, has accused Mr Depp, 57, of verbal and physical abuse throughout their relationship - allegedly punching, slapping, kicking, headbutting and choking her, as well as displaying "extremely controlling and intimidating behaviour".
Depp, however, says he was not violent towards Heard, claiming it was she who was violent to him.
Heard told her mother in a series of texts in March 2013 that he was "raging" and "violent and crazy", but denied he had hurt her, suggesting in court that she did it to protect her mother because of her own father's violent history.
Heard told the High Court: "I was trying to have someone to talk to who would understand how I felt. My father was violent to my mother growing up. They loved each other, but he was very violent to her until the end. My dad struggled with alcohol issues his whole life, an addict and alcoholic, very violent but I loved him very much."
She texted her mother in March 2013 - early in their relationship - to say: "He makes dad looks like a saint when he falls off the wagon", later saying: "I can't tell dad."
The text exchange came a few hours after Depp had allegedly tried to set a painting on fire with his lighter while high on cocaine and whisky after accusing Heard of having an affair with its painter, her former partner Tasya Van Ree.
She added that she didn't tell her mother the truth about the violence at that time because she "just didn't want her to tell my dad".
The actor allegedly "shoved" Ms Heard into a wall and hit her in the face when she tried to stop him setting the painting on fire, drawing blood with his rings which sprayed onto a nearby wall.
In one text Ms Heard wrote: "My heart is broken. I'm ok physically. JD didn't hit me or anything last night. I told him that would be if he did and it worked last night. But I'm scared by what I see and who I see now. It's Dr Jekyll and Mr Hyde - on a binge."
She later texted: "It's OK mom. He's not being violent with me. He's just even raging in general. And the crazy mood swings and binges are really difficult for me to handle", adding moments later: "He's nuts mom. Violent and crazy. I am heartbroken that THIS is who I love".
Amber Heard's texts to her mother
He makes dad look like a saint when he falls off the wagon (March 23, 2013)
My heart is broken. I'm OK physically. JD didn't hit me or anything last night. I told him that would be if he did and it worked last night. But I'm scared by what I see and who I see now. It's Dr Jekyll and Mr Hyde - on a binge. (March 22, 2013)
I feel like I'm on a very fastening train that's about to explode but I don't want to jump off and leave my love behind. So I stay on the train. Even though I know it's about to explode. (March 22, 2013)
It's OK mom. He's not being violent with me. He's just even raging in general. And the crazy mood swings and binges are really difficult for me to handle. (March 22, 2013)
Dealing with Johnny's spiral. It's terrible mom. I don't know what to do. (March 22, 2013)
He's nuts mom. Violent and crazy. I am heartbroken that THIS is who I love. (March 22, 2013)
I can't tell dad. (March 22, 2013)
In another text to her mother read to the court, Heard said: "He told his friends yesterday that he was really lost, but of course when I try to suggest that is part of the fighting, he claims he is not affected whatsoever by it.
"He has been at my house for weeks now. Last night I locked the deadbolt."
Asked by Sasha Wass QC what she was referring to by locking the deadbolt Heard replied: "I couldn't get a moment's sleep... I was either defending myself or trying to make him happy, calm him down, whatever."
Depp tried setting painting on fire after accusing wife of affair with artist
Depp also tried to set a painting on fire with his lighter while high on cocaine and whisky after accusing his wife having an affair with its painter, her former partner Tasya Van Ree, the court was told.
The actor allegedly "shoved" Heard into a wall and hit her in the face when she tried to stop him, drawing blood with his rings which sprayed onto a nearby wall.
Heard claims that Mr Depp refused to leave the couple's house to meet his idol, the Rolling Stones guitarist Keith Richards, on the set of a documentary in order to carry on the argument, saying: "He wanted me to admit that I was having an affair with Tasya."
She told the court: "At one point he tried to set the painting on fire with his lighter. He hit me in the face with the back of his hand and drew blood, some of which ended up on the wall. At various points he grabbed me hard, shook me, and shove me into a wall. I couldn't calm him down - he was so angry and just wouldn't let it go."
During her evidence, which began on Monday, Heard claimed Depp pushed Kate Moss down a flight of stairs, blamed faeces found in the couple's bed after her 30th birthday on one of their pet dogs and denied having an affair with Tesla founder Elon Musk.
On Wednesday Hollywood make up artist Melanie Inglessis said Heard told her Depp had tried to suffocate her with a pillow, dragged her by her hair and "tried to kill" her at the couple's LA penthouse in December 2015.
The actress has described the alleged incident as "one of the worst and most violent nights of our relationship".
Heard alleges Depp slapped her, dragged her by the hair through their apartment, pulling clumps of her hair out, and then repeatedly punched her in the head, which he denies.
Inglessis told the High Court that she had to apply concealer and lipstick to Heard's face to cover the bruising so she could go on James Corden's prime time talk show.
Giving evidence via video link from LA, Inglessis said: "She said 'Johnny and I had a fight', she said he tried to suffocate her with a pillow, she felt he tried to kill her that night and dragged her by her hair."
Describing Heard's appearance the day after the alleged attack, Inglessis told the High Court: "She had minimal discolouration by her nose, her left eye a little more bruised than her right eye, the bridge of her nose swollen and I remember a scab to the right of her lip."
She added: "I tried to conceal some of the bruises with full face of makeup. We had no other choice but to do a bright red lip [stick] to cover the injury on her lip."
Heard will conclude her evidence about 14 allegations of domestic violence, which The Sun's publisher News Group Newspapers (NGN) relies on in its defence of an April 2018 article that called Depp a "wife beater", at the Royal Courts of Justice in London on Thursday.
Her sister Whitney Henriquez, who previously lived in one of five penthouses owned by Depp in the Eastern Columbia Building in Los Angeles, is due to give evidence on Thursday afternoon.
Heard denied telling "lies" about her claims Depp was violent after the actor's barrister Eleanor Laws QC accused her of "instigating the assaults and rows" and "concocting" the allegations against her ex-husband in response to other witnesses' evidence.
Heard told the High Court the star threw bottles "like grenades" during an explosive row in Australia in which the Pirates Of The Caribbean star lost the top of his middle finger in disputed circumstances.
Heard told the court: "He started picking them up one by one and throwing them like grenades.
"One after the other after the other, in my direction, and I felt glass breaking behind me, I retreated more into the bar and he didn't stop.
"I was too scared to look behind me. He threw all the bottles that were in reach, all except for one which was a celebratory magnum-sized bottle of wine."
Depp is suing NGN and The Sun's executive editor Dan Wootton over the publication of an article on April 27 2018, with the headline: "Gone Potty: How can JK Rowling be 'genuinely happy' casting wife beater Johnny Depp in the new Fantastic Beasts film?"
His lawyers say the article bore the meaning there was "overwhelming evidence" Depp assaulted Heard on a number of occasions and left her "in fear for her life".
NGN is defending the article as true, and says Depp was "controlling and verbally and physically abusive towards Ms Heard, particularly when he was under the influence of alcohol and/or drugs".
The case, the biggest English libel trial of the 21st century, is due to finish next week with closing submissions from both sides' legal teams on Monday and Tuesday.