FAIRFAX, Va. • Amber Heard said she knew she should leave Johnny Depp the first time he hit her, but she couldn’t bring herself to do it.

“I knew I couldn’t just forgive him, right, because that means it will happen again. Like, I’ve seen the health class videos,” Heard told jurors through tears as she took the stand in Depp’s libel lawsuit against her.

“I was heartbroken.”

Heard said she walked away after being slapped, but a few days later Depp came back with an apology, a few cases of her favorite wine, and a promise he’d never do it again.

“I wanted to believe him, so I chose to,” she said.

Depp, 58, is suing Heard for libel in Fairfax County Circuit Court after she wrote a December 2018 op-ed in The Washington Post describing herself as “a public figure representing domestic abuse.” The article never mentions Depp by name, but Depp’s lawyers say he was defamed nevertheless because it clearly referred to accusations she made in 2016 during their divorce proceedings.

Much of the trial has focused on whether Heard was in fact abused, something Depp denies.

Heard took the stand for the first time Wednesday.

She also described a time she said she was sexually assaulted by Depp as he angrily performed what he called a “cavity search.”

She said the two of them and some friends had gone to the Hicksville Trailer Palace in Joshua Tree, Calif., in May 2013 for what was going to be a nice night in the desert.

They ingested psychotropic mushrooms, and Depp became jealous when he saw another woman acting in what he perceived as a flirtatious manner with Heard.

Heard said she and Depp went into one of the trailers, which he promptly trashed. He then accused her of hiding his drugs, ripped her dress and started patting her down, she said.

“He was telling me, ‘We’re going to do a cavity search,’” she said through tears.

“He just shoved his fingers inside me. I just stood there, staring at the lights.”