Sir Mick Jagger reportedly spent millions helping L'Wren Scott's business.
The Rolling Stones rocker - who has an estimated wealth of around £200 million - was said to be "hugely supportive" of his late partner, who was found dead in an apparent suicide on Monday (17.03.14), and did his best to get her fashion label out of debt.
However, L'Wren - who hanged herself in her New York apartment - was "embarrassed by what had happened" financially.
A source told the Daily Mirror newspaper: "L'Wren was left terribly upset by what was going wrong with her business, none more so than when she was forced to cancel her London Fashion Week show in February.
"She was a proud woman and understandably embarrassed by what had happened. While Mick was there for her every step of the way trying to help out as best he could, the situation must have put pressure on their relationship."
L'Wren was forced to cancel her London Fashion Week show in January saying at the time fabrics arrived too late for samples to be sewn for the event.
However, insiders claim she made the decision to mask her huge financial problems, with accounts filed for her business LS Fashion LTD in October 2013 showing a deficit of £3,546,000 and the designer owing creditors £4,593,000.
The friend said: "She blamed the fashion week debacle on production delays but this was masking the huge financial problems her company had.
"In the cut-throat world of fashion, reputation is everything and it must have been a huge personal blow to pull the show. Her fear of failure in her peers' eyes may, ultimately, have been too much."
Jo Wood, the ex-wife of Mick's Rolling Stones bandmate Ronnie Wood, said she believes L'Wren's financial situation was the final straw for her.
She told CNN: "Well, maybe, if anything the financial thing might have been the trigger, because she was such a proud woman that I think to face that, well maybe that was the trigger. I don't actually know, I'm surprised as much as everyone else."

Sir Mick Jagger was "totally devoted" to girlfriend L'Wren Scott.
Friends of the Rolling Stones singer, whose partner was tragically found hanged in an apparent suicide at her New York apartment on Monday (17.03.14), have rubbished claims he had ever been unfaithful to the fashion designer and revealed he is "heartbroken" by her death.
A pal told The Sun newspaper: "He had no desire to mess around with other women.
"They spent so much time together Mick was totally devoted to L'Wren. The pair were very much in love. He is heartbroken. He's in bits at the moment."
The 70-year-old singer, who had been dating L'Wren, 49, since 2001, were as close as possible in the months leading to her death, according to the friend.
Mick, who had landed in Australia for the start of the Rolling Stones' world tour was preparing for a gig in Perth when he was told the devastating news.
He is currently holed up at the Hyatt Hotel after the Stones cancelled their entire tour of Australia and New Zealand and is said to be "utterly devastated and bereft".
Mick is being comforted by his daughters Lizzy, 30, and Georgia May, 22, from his marriage to Jerry Hall.
A friend has also claimed the 'Brown Sugar' star has not slept since hearing the news and the tour doctor is currently on call.
The pal told the Daily Mirror newspaper: "He is totally devastated and just wants to be surrounded by his family. We have never seen him so despondent and are extremely worried about him.
"He didn't sleep after being told the news. How could you? Like anyone, he is wrestling with how it happened and if he could have prevented it.
"Of course, there is nothing he could have done but that doesn't stop him feeling utterly tormented by the turn of events. Every waking moment he's been thinking of their last hours and days together and if he could have spotted any warning signs. It's all terribly sad."

George Michael was locked up in prison with paedophiles and bullies.
The 60-year-old singer was sentenced to eight weeks in prison in 2010 after being caught driving under the influence of drugs, and although he only served half of his sentence he claims the few days he spent at London's Pentonville prison alone would've been enough to scare him into sobriety.
He said: "The clearing house you go to is the one that's closest to the magistrate's court you've come from.
"So unfortunately for me, my closest was Pentonville, so I went in there, which was really quite a horrible experience, and I was put in with the paedophiles and the bullies I suppose ... I didn't leave my cell very much in those few days."
The 'Faith' hitmaker was then moved to the Highpoint prison in Suffolk, East England, where he served his four weeks behind bars, but he says as soon as he had recovered from the crash he had begun getting sober.
Speaking on BBC Radio 2, he said: "From the moment the last crash happened [I started to get sober] because apart from anything else, I realised it had to be something to do with me.
"It kind of shook me out of my denial in the way that the others hadn't. Probably because there was a chance I would go to prison.
"So from the day after that crash happened I started in drug counselling, and I was two weeks in detox, none of which I made public."
George - who has just released his new album 'Symphonica' - also confessed that his behaviour was "out of character" and "irresponsible" and says as soon as he came out of prison he experienced a "burst of creativity" and began working on new material.

'Star Wars: Episode VII' will begin filming in the UK in May.
The latest installment in the space opera franchise will be shot at the Pinewood Studios near London in two months time, and will be set 30 years after 1983′s 'Return of the Jedi', producers have confirmed.
A press release issued by Disney and Lucasfilm said: "[It] will star a trio of new young leads along with some very familiar faces."
Adam Driver is in talks to play the villain in the film, which will be directed by J.J. Abrams, but others battling it out for lead roles include, Ed Speleers, John Boyega, and Jesse Plemons.
It is thought Lupita Nyong'o has also met with famed director Abrams to discuss taking on a female lead role in the upcoming sequel after she took Hollywood by storm last year following her impressive performance in Steve McQueen's '12 Years A Slave'.
Meanwhile, it is believed the stars of the original trilogy, Mark Hamill, Harrison Ford and Carrie Fisher, will also appear in 'Episode VII'.
The highly-anticipated sci-fi adventure was originally thought to centre on Han Solo and Princess Leia's kids, however, Abrams and Lawrence Kasdan's recent rewrite of Michael Arndt's script has allegedly altered the focus.
'Star Wars: Episode VII' is set for release on December 18, 2015.

The Rolling Stones have postponed their upcoming Australian and New Zealand tour.
The band are "deeply sorry and disappointed" to announce that they've put the first leg of their '14 ON FIRE' tour on hold following the death of Sir Mick Jagger's girlfriend L'Wren Scott.
A statement released on their website read: "The Rolling Stones are deeply sorry and disappointed to announce the postponement of the rest of their 14 ON FIRE tour of Australia and New Zealand following the death of L'Wren Scott.
"Mick Jagger, Keith Richards, Charlie Watts and Ronnie Wood wish to thank all of their fans for their support at this difficult time and hope that they will fully understand the reason for this announcement.
"The Rolling Stones are planning to reschedule these postponed shows at a later date."
The group initially cancelled their Perth gig, which was scheduled to take place tonight (19.03.14), but they've now decided to abandon the rest of the dates while the frontman comes to terms with his loss.
L'Wren, 49, who has dated Sir Mick Jagger since 2001, was found hanged in an apparent suicide at her New York apartment on Monday (17.03.14).
The Rolling Stones private jet is still in Perth, but it is unknown whether Sir Mick has flown out of Australian and back to New York.

Ashley Roberts says Ant and Dec are "so down to earth".
The former 'Dancing on Ice' judge hosts the 'Ant vs Dec' segment on the presenting duo's hit show 'Saturday Night Takeaway' and she is thoroughly enjoying working with the TV veterans.
Ashley exclusively told BANG Showbiz: "I love it! I'm so blessed, my life right now, I'm getting to do so many things I love to do over here in London and to work with the boys ... they're just so cool, so down to earth. They're so professional and so great at what they do, so I'm so grateful to be part of such a massive show and the team that also works behind them is cool as well."
The 32-year-old beauty hasn't had any advice from Ant and Dec, but says the Geordie duo are incredibly supportive of her burgeoning TV career.
She added: "They're just like, 'Ash, yeah, you're gonna do good.' They're just supportive. When we're there for rehearsals, it's like, they have so much going on that the last thing they need to worry about is me. But we just have good fun and a good laugh."
Ashley's new perfume 'Ashley by Ashley Roberts' will be available to purchase from The Perfume Shop, keyfashion.co.uk, very.co.uk and Argos from 12th March and comes as a 100ml EDP retailing at £21.99.

'EastEnders' newcomer Charlie Cotton will raise suspicion as Dot Branning prepares for her son's funeral next week.
Dot - played by June Brown - recently learned her wayward offspring Nick Cotton has died and is determined for him to be brought home to Albert Square before being buried.
The Walford matriarch tasks her long-lost grandson Charlie (Declan Bennett) with bringing Nick home, but having prepared herself to view the body, she is dismayed to discover the coffin is screwed shut.
When Dot requests for the lid to be unscrewed, Charlie and funeral director Les Coker begin behaving oddly, suggesting all is not as it seems.
A source told Inside Soap magazine: "Why should it matter to them that Dot wants to have a final moment with Nick? Surely, given the state Dot is in, they'd want to help ease her grief in any way they could. It's quite odd."
The residents of Walford will rally around Dot in her time of need, even though many of them despised villainous Nick, played by John Altman. Ian Beale (Adam Woodyatt) is even tasked with writing a eulogy for the man who burned down his café in 2009.
The insider added: "Whatever Nick did, everyone loves Dot and they want to be there for her. If Nick could see them all he'd cackle up a storm, but his mum is precious to many."

Cara Delevingne and Michelle Rodriguez are planning to attend their first music festival together.
The 21-year-old model and the 'Machete Kills' actress have been inseparable over the past few months, and they're now keen to make their relationship even more public by attending Coachella in California as a couple next month.
A source told The Sun newspaper: "Cara and Michelle are getting more and more serious.
"They've already been away as a couple to Thailand and now want to go to their first festival together.
"Cara is a big festival-goer and this is a dry run for Glastonbury. She loves the Somerset event and wants to take Michelle this year to experience it too."
The pair first sparked rumours they were dating after they were spotted cuddling up to each other while watching the New York Knicks defeat the Detroit Pistons at Madison Square Garden back in January.
It is now believed Cara - who was once romantically linked to One Direction hunk Harry Styles - is so smitten with the 35-year-old star that she wants to tie the knot with her at the Niagara Falls in Canada.
A source said previously: "It's typical of Cara to want to do something crazy and impulsive. But she seems deadly serious.
"They've talked about what kind of big day they'd have. Cara says she wants them to wed in their own element with no priest or anyone with a religious background."

L'Wren Scott envied her sister's "simple life".
The designer, who had been dating Sir Mick Jagger since 2001, was found hanged in an apparent suicide at her New York apartment on Monday (17.03.14), and her sibling Jan Shane, 53, believes she was unhappy with her jet-setting life.
Jan told the Daily Mail newspaper: "To me she had it all.
"She was going out with a Rolling Stone and travelling to London and all around the world and I was a stay-at-home mum who hasn't really been anywhere."
Jan, who has eight children and has been married for most of her life to the local binman, admits it was at her father's funeral in 2002 that she realised all wasn't well in her sister's life.
She explained: "It was hard to get near her. I don't know why she thought she needed bodyguards at our father's funeral. I guess that's just how her life was at the time.
"But at one point we stepped out together and she looked at me and said, 'I envy you.'"
The siblings, who were adopted along with their brother, haven't spoken since 2008 at their mother Lula's funeral, but Jan believes she could have prevented L'Wren's death given the chance.
She said: "It is really sad. I wish we were closer. I would have always sat down with her to talk things over if she was struggling.
"We had no clue she was feeling like this. She must have felt so alone and it bothers me because she always had us. I would have talked to her in a heartbeat. I just hope she knew that."
It is believed L'Wren was almost $6 million in debt when she died and had reportedly been "acting strangely" in recent weeks.

Cameron Diaz says "everyone will be cheated on".
The 41-year-old actress - who plays Carly, a woman who unknowingly dates a married man, in comedy 'The Other Woman' - insists she doesn't want to make movies about men cheating on women, but believes most people have, or will, experience betrayal at some point in their lives.
She told OK! magazine: "I didn't make the movie to make a statement. My statement is that I'm actually not interested in making movies about men cheating on women, it's not at all what I am interested in.
"Everybody has been cheated on, everyone will be cheated on. I can't fix that, I don't know how, I don't have any judgement on anybody, I don't know how to fix the problem."
Diaz believes all humans suffer at one point in their lives but thinks they should learn from their errors.
She added: "We are human beings, we are complicated - you cannot go through life without tallying up a few scars, you cannot go through life unscathed, it's just what it is. It's all meant to happen, take your lessons, figure it out, move on."

Jake Bugg found it "easy" working with Rick Rubin.
The 'Lightning Bolt' singer, who worked with the famous producer on his second album 'Shangri La' at his Malibu recording studio and claims it was a simple process.
He told Faster Louder: "Despite if I knew him or not, I had enough people telling me the reputation he had, so I just didn't think it was an opportunity to turn your nose up at.
"You might learn something, you might get something out of it, you might not, but you'll definitely learn something.
"The experience as a whole was great, he brought in great musicians. I just had a load of ideas, and I'd sit down and teach the band. He'd drag those ideas out of me and make sure I turn them into songs."
Jake added: "It was just pretty relaxed, we'd record a song four or five times and then onto the next. Pretty easy."
The 19-year-old singer admits the idea of working with Rick, who has recorded with the likes of Ed Sheeran, Kanye and Eminem, could be intimidating for some artists but he felt "free" to work on his own material.
He added: "What Rick does is different to what I do. It's his job to produce and it's my job to play the songs. It worked pretty well, it was just a chilled atmosphere to be honest."

George Michael is embarrassed by the fact he had blonde hair in the 1980s.
The 'Faith' hitmaker - who shot to fame alongside Andrew Ridgeley as a member of Wham! - also finds it 'cringe' when he looks back at old videos on YouTube, in which he wore hoop earrings.
George explained: "Where do I start? I know - the blonde hair from my Wham! days. That came about because I didn't really want to be me, so the short, dark, curly hair had to go. And I could have done without those curtain rings in my ears as well."
The 50-year-old star also regrets placing shuttlecocks down his shorts during performances on their first tour to make his 'package' appear bigger.
He said: "I mean, how stupid was that? Actually, that one I'll blame on Andrew - he really loved winding people up all the time.
"I do remember another embarrassing moment from the old days ... when Andrew and I went to a music awards ceremony early in our career. I was wearing a suit that made me look a bit like Colonel Sanders and I was practically orange from overdoing it on a sunbed."
But George laughed off the disastrous look as he was still "experimenting" with fashion and his talent was more important.
He added in an interview with Britain's HELLO! magazine: "One thing I didn't have any doubt about, though, was my songwriting. I had a pretty unstoppable belief in my talent and once I had a foot in the door of the music industry, nothing was going to shift me."