New Documentary Reveals the Untold Story of Yves Saint Laurent

By Liz McNeil

07/18/2014 at 07:10 PM EDT

A fragile genius once described as having been "born with a nervous breakdown," Yves Saint Laurent who died of brain cancer in 2008 at 71, transformed trends, popularizing the peacoat and the pantsuit, now considered basics.

Says his business and one-time romantic partner Pierre Bergé, "He invented the modern women's wardrobe."

Now six years after his death, a new biopic, Yves Saint Laurent in select cities nationwide, reveals more of the decadence behind the glamour.

Plagued by depression, Saint Laurent abused alcohol and cocaine for many years.

As he said at the time of his retirement in 2002, "I have been through sheer hell. I have known those fair-weather friends called tranquilizers and drugs ... but through it, I was able to rise to the heavens of creativity."

That's the legacy that Bergé, 83, wants people to remember.

"Yves often said the most beautiful clothes that can dress a woman are the arms of the man she loves," he says. "But for those who have not had the fortune of finding this happiness, I am there."

For more on the legendary designer, pick up a copy of this week's PEOPLE, on newsstands now