'Elon is my best friend... you'd think our marriage would have worked': Actress who is divorcing tech billionaire talks about giving up her career to care for his children

Billionaire Elon Musk's British wife Talulah Riley has opened her heart about the couple's on-off, on-off relationship five months after she sued for divorce for a third time.

The couple first met in 2008, when the actress was a virgin, and they got married two years later.

But their first marriage ended in divorce in 2012, with Riley reportedly walking away with a $16million divorce package. 

The odd couple: Elon Musk (left) reportedly took Tallulah Riley's virginity when they met in 2008 and although they are set to divorce for a second time she says she still loves him 

By the following summer they had remarried but then in December 2014 she sued for divorce a second time, only to withdraw it the following year.

Riley first made her name in Pride and Prejudice and has had small parts in Inception and Thor: The Dark World without really making it big.

In March this year she filed for divorce again and is set to cash in on an even bigger financial settlement this time. 

But in an interview with The Times today Riley said: 'We really are best friends. I'll always love him, I'll always be there for him.'

Journalist Stefanie Marsh said that sounded like the basis for a good marriage, and Riley smiled before replying: 'You'd think.'

She was 22 when she met Musk - almost 20 years her senior - in a London nightclub. 

She was the product of two of British's poshest and most expensive schools - Cheltenham Ladies College and Haberdashers’ Aske’s School for Girls. 

Earlier this week she told the Mail on Sunday's You magazine how the tycoon - who founded the SpaceX aerospace company - had chatted her up by offering to show her his rockets.

Talulah with her on-off husband Elon Musk at an Oscars part in 2014

‘I was sceptical, but he actually did show me rocket videos,' she added. 

Asked if she would marry Musk for a third time she said: 'I mean, never say never. Marriage is a social construct, but I still believe in it. 

'Elon and I are best friends. We still see each other all the time and take care of each other. If this could continue indefinitely it would be lovely. When you’ve been with someone for eight years on and off, you really learn how to love them. He and I are very good at loving each other.'

Musk was seen partying this week at London celebrity hotspot The Box with actress Amber Heard. 

Johnny Depp's estranged wife has denied she is dating him but they have been spending a lot of time in each other's company.

Heard would fit the pattern for Musk's love interest.

On, off, on, off: Tallulah Riley and Elon Musk, pictured together in Italy, have had a bizarre relationship but it appears their second marriage is coming to an end

Like Riley and his first wife Justine Musk, a Canadian fantasy author, she is good-looking, slim and blonde.

An embittered Justine claimed Musk - with whom she had five children - made her into a trophy wife and pestered her to dye her hair blonder.

Of Justine, Riley told The Times diplomatically: 'I believe that everyone's entitled to share their version of the truth. I don't see it as my job to clear the record.' 

Riley's acting career has stalled in recent years but she will soon be appearing as a robot in the HBO TV remake of the cult 1973 sci-fi movie Westworld.

But she said she was happy to give it up to care for Musk's five sons. 

Riley has recently published a novel, Acts of Love, which is set around the relationships of Silicon Valley entrepreneurs. 

She is adamant the story is unrelated to her life – 'I don't consider writing the book as therapy' – and that Musk was not the inspiration for the main male character, Radley Blake: 'He's entirely out of my own head'. 

Riley also denies she herself is the basis for the main female character, Bernadette, although she is attractive and British.

'Hopefully not too much. I don't condone her behavior. Although her longing to be better and not reaching those standards – I can relate to that,' she says.

Still a virgin when they met, within weeks Riley moved to LA to live with Musk and his five young sons (twins and triplets) from his previous marriage to Justine Musk.

She flew around in his private jet, holding lavish parties, attended Obama's inauguration and had a romantic zero-gravity flight over California, with Titanic director James Cameron playing gooseberry. 

Talulah Riley, whose father is a former senior police officer in England, is an actress but has recently got involved in a start-up app based in Silicon Valley  

'I've had lots of fun experiences. It’s just been, you know, life,’ she shrugs. ‘It’s been my 20s.’

Riley now works long hours in a small office in San Francisco, alongside co-founder Stacey Ferreira, a 23-year-old Silicon Valley rising star and Talulah’s housemate. 

The duo raised $1.5million from investors to get their project - Forge - off the ground. 

Forge is an an app launched earlier this year that allows low-paid retail and restaurant staff in the US to schedule their own working hours. 

Businesses post shifts and workers sign up for their choice of hours at companies they are approved to work for. 

She says: 'I learned a lot about business and Silicon Valley from Elon and having a front-row seat for eight years, which was fantastic.'