A FASHION tycoon has accused her ex-partner of living a double life consisting of “rampant” drug use, prostitutes and sordid affairs.

Net-a-Porter founder Erik Torstensson is alleged to have confessed to being a “liar, drug addict, alcoholic and sex addict” as his relationship fell apart, according to a bombshell lawsuit.

A civil case has been launched in California by former chairman of the British Fashion Council Dame Natalie Massenet, 60, after her 14-year relationship with Torstensson ended earlier this year.

Court papers show the female fashion queen was left “heartbroken” after they split as she claimed to have uncovered a trail of deceit.

Trouble started for the couple when Torstensson, a 47-year-old Swedish entrepreneur, started to frequently disappear at night and began drinking heavily, the suit claims.

Massenet also alleges that she found a bottle of Valacyclovir in the home which he said was to treat hives.

She later learnt it was actually to treat herpes, her lawyers said in the suit.

By the end of 2024, the couple had started counselling but Torstensson’s behaviour only continued to deteriorate.

Dame Massenet alleges that in May she uncovered a secret life that she believes Torstensson had been living “for many years”.

The lawsuit claims to shows explicit messages and photographs showing her partner and other women.

Court documents allege these are proof that he “maintained multiple affairs with several younger women” – some of whom the dame had met in the past.

When she confronted Torstensson after finding the texts on his phone, Massenet claimed he confessed to being a “liar, an alcoholic, a drug addict, a sex addict and that it had gone on for seven years”.

Her lawyers also claim Torstensson hired prostitutes and used drugs including cocaine in Los Angeles, London and New York while travelling for work.

One sex worker was allegedly hired just days after the couple celebrated their son’s embryo being implanted with a surrogate.

Another alleged text came from a family holiday where Torstensson told another woman he was “in hell” on the trip.

Torstensson also faces accusations of using Massenet for his own “social clout”.

She claims in the suit to have spent more than $95million during their relationship on properties, vacations, and expensive goods which the couple shared.

Torstensson had promised to pay her back “in kind”, according to the court documents.

The suit alleged: “As soon as he had finished spending Massenet’s money, he left.”

Her lawyers claim the Swede targeted Massenet as he was trying to forge a “path toward power, influence and a better life”.

The successful businesswoman was made a Dame by Queen Elizabeth in 2016 and was friends with A-listers such as David and Victoria Beckham.

Many of Massenet’s celebrity pals would even go on to promote Torstensson’s Frame brand which became a global success.

Lawyers for the Dame claim: “Torstensson had schemed to defraud Massenet out of her hard-earned money and convince her to use her influence and finances to promote and endorse Torstensson publicly and privately under false pretences.

“When the romantic relationship ended because of his duplicity, and as her cash ran out, he cut Massenet out of any potential earnings from her significant investment in Torstensson over the last nearly 15 years.

“While Massenet is emotionally devastated and in shock caused by Torstensson’s outrageous behaviour, this is a case of a return on investment in a man who leveraged Massenet’s capital and brand to build wealth, while she bore the majority of the costs.

“Massenet is demanding what any investor would – a fair, equitable return on the investments she made, value she created, and costs she carried.”

Her lawyers also say the self-made entrepreneur suffered from severe emotional distress which has left her needing intensive therapy and take time off work.

Torstensson is yet to file a response to the claim.