Dad-of-two Roger Griffiths, 42, used to drive a Porsche and vacation with the super-rich in New York and Monaco.
He and wife Lara lived in a £670,000 home, sent their children to a £10,000-a-year private school and plotted to double their wealth through property and stock market investments.
Roger also splurged on a fleet of fancy cars and luxuries like tailor-made suits and Cartier diamond jewellery.
He even blew £25,000 making a record after getting his old student band back together. They sold just 600 CDs.
Roger said: "I loved being rich. There were times when I didn't look at price tags and that was ludicrous, stupid — but I loved it."
Roger and Lara flew to Dubai, Florida and Majorca in the months after his win.
They bought champagne by the case and partied with celebs like Take That as they enjoyed the millionaire lifestyle.
But their fortune was wiped out by a failed business venture — and the global financial crisis of 2007. Their 14-year marriage collapsed because of rows about money and the business was sold at a loss.
Roger, who once earned £340 a day in interest, now has just £7 in the bank.
He said: "I had it all, but now it's gone. I've been borrowing money from my parents — that's how bad it is.
"I feel ashamed to say this but I haven't been smart enough. I thought I was bright — degree-educated, pretty astute. I thought I could make it work for me and I failed.
"I'm trying desperately to keep the wolf from my door but I'm running out of ideas."
Roger had quit his IT manager's job after scooping £1,831,492 (US$2,784,104) in 2005. He and Lara spent £200,000 buying and renovating a beauty salon to provide a steady income.
But their Lotto dream turned into a nightmare after the crisis of 2007 halved the value of their investments.
The housing market also collapsed and the beauty salon began losing £4,000 a month.
Roger and Lara had borrowed against the value of their home to set up the salon, and felt they had no choice but to keep "pumping money into the business".
They withdrew £100,000 from their remaining investments to stay afloat, but saw it swallowed up by bills.
Roger said: "We had vowed never to drop below £1 million, but we were just living off the lottery money.
"There was no adding to it, no protecting it. We weren't getting £340 a day interest and the investments had vanished.
"We were hemorrhaging money. It was awful. There was nothing to plug the dam.
"And once you have tasted that life of a millionaire it's difficult to step back. The pressure on us was enormous."
In December 2010 the couple's home went up in flames, destroying possessions worth £120,000, and a few months later their marriage was over. Lara, 43, stayed in the marital home while Roger moved into a two-bedroom house in Harrogate, North Yorks, that he bought as an investment.
The house is almost empty after Roger sold off most of his possessions to make ends meet. He said: "I walk around the house sometimes wondering, 'How did it come to this?' To a certain extent I have only myself to blame, but I also feel cheated by the financial crisis. My luck stopped when I won the lottery.
"I loved every minute of it but it also put massive pressure on me. I thought I was clever enough to make something bigger happen from it."
Roger now works as a self-employed recruitment consultant, but admits: "The money I bring in goes on bills I racked up during the heyday and there's just not enough to cover them. If it wasn't for my family helping me financially I'd be in trouble. Looking back the lottery win was like a poisoned chalice."