They first met when she was aged just 14 and he was 37, and went public with their relationship five years later, when his previous wife left him.
At the time, Marke was considered to be one of Britain's leading martial artists and was the head of the World Congress of Martial Arts Association.
Phythian admitted their relationship caused something of a stir at the time but she denied being infatuated with him.
She described how she got her first movie break after being spotted at a martial arts competition in the United States.
In 2016, she landed the role of Brunette Zealot in Doctor Strange and she was described as enjoying "unprecedented personal and professional success".
She has also starred in other martial arts action movies such as Tribal: Get out Alive, and another due out this year.
The court heard she also ran a martial arts school in Mansfield as well as owning an entertainment and production firm and a clothing brand.
But in 2017 she was arrested alongside her husband when a woman came forward alleging the couple had repeatedly sexually abused her from the age of 13.
The victim described how the couple plied her with rum, before Phythian invited her to play a game of "dare", asking her to copy a sex act she performed on Marke.
Giving evidence, the woman, who cannot be named for legal reasons, described the couple as being like "Jekyll and Hyde" and said they had threatened her and forced her to film some of the abuse.
She said the couple had abused her once or twice a month from 2005, and said Marke had sex with her on at least 20 occasions.
Phythian denied the allegations, but the victim was able to describe in detail a tattoo that the actress had in an intimate area of her body.
The victim told the court: "I just did whatever they asked me to do. I just felt like there was no way out. They told me not to say anything."
Marke, who repeatedly broke down in the witness box, denied that he was attracted to girls aged in their early teens.
He also rejected prosecution claims that he and Phythian had "encouraged threesomes" when their victim was between the ages of 13 and 15, telling the jury: "It's not the reality at all."
Phythian denied all the allegations, telling the court: "I am not a paedophile, or a rapist. Nor is Vic."
But jurors unanimously convicted the couple after deliberating over two days.