Ambitious: Michelle says she's still working out what she wants to do with the next chapter of her life

She’s one of Britain’s most flamboyant businesswomen. Now Ultimo bra tycoon Michelle Mone is laying bare how her marriage became a battle more bitter than any she’d faced in the boardroom. Today, in our concluding extract, she reveals how she finally exposed her husband’s affair — and plotted her revenge . . .

As a kid growing up in one of the most working class parts of Glasgow, I vowed that one day I’d have a house like the ones I saw on my favourite TV programme, Dynasty.

Sure enough, the six-bedroom mansion which my husband Michael and I bought in 2008 had a sweeping staircase, just like the one featured in the home of the fabulously wealthy Carrington family.

There was also a huge walk-in wardrobe containing 100 pairs of Louboutin shoes and racks of dresses costing £4,000 a pop.

Downstairs we had a bar, a cinema with reclining leather chairs and even a nightclub out the back, not to mention five flashy cars on the driveway including Michael’s £100,000 Porsche.

To top it all, the house was in an affluent village ten miles from Glasgow which is known as Millionaires’ Row. For me, it couldn’t have been more perfect — but my parents hated visiting me there.

‘It’s like a show-home,’ Mum shuddered, and she was right. I had installed four dishwashers because I couldn’t bear the sight of dirty plates, and our three kids were forbidden ever to put a pine coat-hanger into a walnut wardrobe, knowing that it would freak me out.

Once I returned from a business trip and found that the salt grinder had been left out in the kitchen. Panic. I needed to check nothing else was out of place.

Only after I’d opened the cupboards one by one and ensured that the food labels were all facing the same way did I feel in control again.

This obsessive compulsive behaviour was a manifestation of my deep-seated unhappiness. I found comfort in regimenting the small things around me because I felt out of control in a much bigger part of my life — my marriage.

As I’ve explained in this series, my marital problems began soon after the launch of our Ultimo lingerie brand in 1999. Going to work became like walking through a minefield, our boardroom meetings constantly interrupted by one or other of us storming out, and the arguments continued at home where our sex life was virtually non-existent.

Incredibly, I never considered divorce. I came from a background where you got on with it, no matter what. But the beginning of the very dramatic end came in the summer of 2011 when I appointed 31-year-old Samantha Bunn as our new head of design.

Break-up: Michelle split with husband Michael after he became close to her new head of design Samantha Bunn

She was nine years younger than me and I took her under my wing. She was having big problems with her boyfriend so I felt sorry for her and said she could live in our guest annexe, right next door to the main house.

I treated her like a family friend. Some nights I invited her over for dinner and we’d all sit around the kitchen table, chatting and laughing. But soon she started pushing the boundaries.

At work, she was always in Michael’s office, flirting and flicking her long dark hair. Michael shut the door, something he never usually did, but I could see what was going on because of the design of our headquarters. Built in the shape of a breast — well, we had made our fortune selling bras — they had glass walls everywhere.

While I was away on business, Sam started popping around for dinner with Michael and the kids. One night I saw him lifting a bottle of red out of the wine rack and he told me he was taking it next door because Sam had texted to say she’d run out. An hour later he returned, claiming they had been just ‘talking’.

After that, I was constantly asking Michael if he was having an affair and his answer was always the same — ‘You’re mad, you need to be sectioned’.

He told everyone, even my parents, that I needed psychiatric help, but my suspicions continued to grow at our office Christmas party where Sam giggled into his ear and he ignored virtually everyone else.

Michelle Mone fired Samantha Bunn (left) after discovering she had struck up a romance with her estranged husband Michael

Michelle hired a private detective to prove that her ex-husband was having an affair her head of design Samantha Bunn

I wanted to go home at 7pm so the staff could let their hair down without us around, but Michael refused to leave. That night, I paced our bedroom waiting for him to return. Finally, at 3.30am, I heard a taxi pull into the drive and the two of them giggling.

That was it. I’d had enough of this heartache and nobody made a fool out of me. I confronted him and we had yet another explosive argument and barely spoke for the next week.

When it got to Christmas Day we agreed that we’d put on a happy front for the sake of the children, who were then 12, 15 and 19, but after taking the turkey out of the oven Michael suddenly walked out.

It was awful. I was crying and so were the kids. He didn’t come back until Boxing Day morning, and we agreed then that our marriage was over. I put out a Press statement to that effect because that way I knew there could be no going back, and I could draw a line under it and finally move on.

The release made no mention of Sam. I was doing this for closure, not out of spite, but Michael remained adamant that there was nothing happening between them, and I wanted proof that there was to reassure both myself and my family that I wasn’t going mad, as he had kept insisting I was.

LET'S GO NEXT DOOR TO THE BEDROOM, SUGGESTED SHANE WARNE Indecent proposal: Warne was 'too wild' for Michelle Newly single after 22 years of marriage, I got a rude introduction to the modern dating scene from the Australian cricketer Shane Warne, Liz Hurley’s ex. We were fixed up by our mutual friend, the former England cricket captain Michael Vaughan. Since Shane was in Australia and I was in the UK, we couldn’t meet straight away and spent two months constantly texting and chatting over the phone. He was good fun, and although I felt the odd text message from him was a bit too explicit, I was excited about seeing him when he flew to London in February 2014. He was supposed to land on a Saturday, and we planned to meet that evening, but I received a text on the Friday saying he had arrived a day early because he had to ‘sort some things out’ with Liz. That happened to be Valentine’s Day, so my mind raced as I wondered whether he was two-timing me. The following evening, I got all dressed up in my suite at the Dorchester hotel, before receiving a text at 7.45pm, 15 minutes after he was supposed to meet me, saying he couldn’t make it. I was furious, and even more so the next morning when I saw newspaper photographs of him getting out of a car with Liz. Later that day, when he asked if he could come and see me, I almost said no, but he insisted so vehemently that nothing was going on between them that I gave him the benefit of the doubt. Since paparazzi were hanging around the hotel for the BAFTA Awards, we agreed that he should come to my suite which had a lounge where we could sit and chat. Finally, after all that build-up, he walked in. We opened a bottle of champagne and talked, but it wasn’t the sort of conversation I’d expected. He chain-smoked about 35 cigarettes — and I hate smoking — and after about an hour he got restless. ‘Can we go next door to the bedroom?’ he asked suggestively. I made it clear that I was not that kind of girl and, besides, though he’s a nice, fun guy, he wasn’t my type in the end. He was a bit too wild for me. All in all, it was really disappointing but at least I learned something from the experience. Never again will I start texting a guy without meeting him first because, quite frankly, Shane wasted two months of my life. Advertisement

So I decided to flush them out like rats. That January, the two of them were due to visit our factories in Hong Kong with some of our technical staff and I gave details of their itinerary to a private detective recommended via contacts of my friend, Carol Vorderman.

I’d got to know Carol well after we starred together on Celebrity Apprentice, and while Michael and Sam were away in Hong Kong she took me out to lunch in London to cheer me up.

Halfway through our meal I got a call from the private detective, suggesting we meet urgently. He came to the restaurant, took me aside, and handed me a big brown envelope.

Inside I found pictures of Michael snogging Sam at the airport and of her going back to his hotel room. Deep down I knew my marriage had been over for years, but I still felt indescribable pain. My knees buckled and I fell to the ground crying, comforted by Carol who ran over and wrapped her arms around me.

Back in Scotland my grief turned to anger. After texting Michael to tell him that he had been caught red-handed, I grabbed a knife and went to town on his beloved Porsche, scratching it to shreds.

Then I charged round to the guesthouse where Sam was living — thanks to the kindness which she had betrayed — and threw all of her possessions into the garden, the dressing table along with them. I was like a banshee.

I then kept calling Sam’s phone until she picked up.

After defacing her husband's Porsche, Michelle had to give Michael £8,000 for the damage to the car

‘You b****, you lied to me,’ I screamed.

‘It’s not like that,’ she stuttered. ‘It only started a few days ago.’

‘You’re a liar and you’re fired,’ I blasted.

When Michael got back from Hong Kong, the first thing he raged about was his Porsche.

‘My f***ing car,’ he yelled. ‘You’ll pay for that.’

‘You’re lucky I didn’t set fire to it,’ I replied.

In the coming weeks, he told the press that there had been no relationship with Sam prior to our split at Christmas — and I even got a letter from her lawyers saying that she was suing me for unfair dismissal.

What was I supposed to do? Sit down and design bras with her? I would probably have stuck the needles and scissors up her backside, but my lawyer advised me to pay her off and she wasn’t the only cost. I also had to give Michael £8,000 for the damage to his car. But the fighting between us was not over even then.

Any reasonable person who’d had an affair would have moved out of the family home, but Michael tried to insist that it was I who should go. There was no way I would leave my house and my kids, and what followed was like that film The War Of The Roses in which divorcing husband and wife Michael Douglas and Kathleen Turner try everything to get each other to leave the house and end up in a fight to the death.

Weight battle: Entrepeneur Michelle Mone went from a binge-eater, left, in 2003, to svelte pin-up, above

Every night there was a race to the master bedroom. Whoever was there first got the bed. I put his favourite shirts and cufflinks in the bin. I let down his car tyres. I cut holes in all his boxer shorts. I put laxatives in his coffee on the day that he and Sam were going to a wedding — God only knows if that worked. Michael probably did things to me too because quite a lot of my stuff went missing, but somehow we remained under the same roof for eight months before agreeing to alternate weeks at the house.

On the day I moved out to a hotel for his first week I crept up to the master bedroom, pulled back the luxurious throw and threw a bucket of cold water over his side of the bed before replacing the covers.

Later the kids phoned to ask why I had done this and, looking back, I can see I was selfish. I should have thought about the effect all this would have on them, but it was my way of getting my hurt out.

At the same time, I was also fighting Michael for control of the company. Who would buy out who? It started with a low blow from him. ‘You’re fired,’ he said one day, pointing at me as if he was Lord Alan Sugar.

I’d always left the legal side of things to him and now learned that he had somehow ended up with 48 per cent of our shares, compared with my 47 per cent. But still he needed 50 per cent to control the business and I managed to persuade Tom Walker, a silent shareholder who owned 5 per cent, to back me, and together we had more power than Michael.

Hidden troubles: Michelle and Michael, above in 2010, maintained the image of the perfect couple

That was round one of what felt like the longest boxing match in history. Whatever punches Michael threw I got up the next day ready for battle.

He might have been more intelligent than me — he was a university graduate whereas I had left school at 15 with no qualifications — but I had more fight and stamina, although I was crying myself to sleep and downing a bottle of wine a night to numb the pain of it all.

With news of our problems now public, the company value crashed as customers wondered what was going on. Eventually I managed to find new backers, but they would only invest if Michael left — and he refused to accept what was being offered for his shares.

Finally, in February 2013, with only weeks to go before we went under, our bank told Michael that he had to accept the deal. That same day I agreed with him the paperwork for our divorce, and soon afterwards we sold the house.

The biggest battle of my life was finally over, and in August 2013 the kids and I moved into a once derelict Victorian building in Glasgow which I had spent months transforming into our new dream home. Living there was a new beginning for us, and the feelings of bitterness which used to eat me up at night slowly vanished.

Not even the news that Michael had launched a rival lingerie company with Sam bothered me, and I wished them all the best on their recent engagement.

As for me, I hope that one day I’ll meet the perfect guy, but I’m not sitting around waiting for it to happen because there’s so much I still want to achieve.

These days I want to spend more time with my kids, and more time working on ‘me’, and so I have sold 80 per cent of Ultimo, hanging up my bra as Chief Executive.

I’m still working out what I want to do with the next chapter of my life. It will definitely involve lots of motivational speaking, inspiring other people to make the most out of their lives, and if there’s one lesson I’ve learned above all, it is that material things do not bring you happiness.

If only I could go back in time and tell that to the little girl who sat at home in the East End of Glasgow, watching TV with her sausage-and-chips supper on her knees and dreaming of the riches she saw on Dynasty.