By Tom Fordyce BBC Sport Online

The news that Cathy Freeman will miss the Commonwealth Games writes another bleak chapter in a life lit up by athletic brilliance but darkened by problems off the track.

Freeman has decided to stay by the side of her husband Sandy Bodecker, who is undergoing treatment for cancer, rather than compete this summer.

Freeman is overwhelmed after winning 400m gold

Two years ago, she provided the defining moment of the Sydney Olympics by taking 400m gold in front of a 110,000 crowd in Stadium Australia.

The manner of the victory was classic Freeman - a wonderful piece of smooth running followed by a celebration that was all her own.

Where others danced laps of honours or posed on the podium, the shy Aboriginal girl from Koori sat cross-legged on the track and put her hand over her mouth in shock.

Freeman's life has been characterised by what another of Australia's Olympic heroines, Raelene Boyle, called her "beautiful vagueness and beautiful toughness".

On one hand she has survived the harshest of backgrounds to become one of the greatest athletes of her era, a potent symbol of modern Australia.

Yet she remains vulnerable to self-doubt and depression and has struggled to cope with the pressure her track success has brought.

"I still have my days when I get really down and feel really lonely," she said last year.

"You feel scared. People sort of put me up on a pedestal. I am supposed to be this really tough athlete now, Olympic champion and all the rest of it.

"But I still have my days where I get depressed and I question my self-worth and feel inadequate."

Freeman's relationship with Bodecker has been dogged by controversy. She was introduced to the man 20 years her senior in 1996 and married him in 1999.

A year later she terminated the contract of former coach and manager Nick Bideau - who just happened to be her former partner.

Cathy Freeman announces her husband's illness at a news conference

Bideau had met Freeman at the Commonwealth Game trials of 1990, when she was just 16 and he was 29.

Bideau and his business partner Peter Jess bought out Freeman's parents, to whom she had signed everything over when she was younger, and created Cathy Freeman Enterprises to manage her affairs.

It was Bideau who advised Freeman to wave the Aboriginal flag after she won 200m and 400m Commonwealth gold in 1994, a gesture which boosted Freeman's profile enormously.

The pair's personal relationship ended in 1996, when Bideau began seeing Sonia O'Sullivan.

But when Freeman ditched him as her manager, six months before their contract was due to come to an end, Bideau sued for breach of contract.

The court case was heard in the run-up to the Sydney Olympics and left enough dirty washing being hung in public to last a lifetime.

Bideau was even quoted as saying that Freeman had threatened to retire when she heard of O'Sullivan's pregnancy in 1998.

Difficult upbringing

Adversity is the common thread that runs through Freeman's roots.

Her grandmother, Alice Sibley, was taken from her mother aged eight and moved to Palm Island, off the Queensland coast.

Her paternal grandfather was Frankie "Big Shot" Fisher, a rugby league player of such prowess that he was invited to come to England to play. But the Queensland government refused to allow him to get a passport.

Her father, Norman, was a brilliant footballer who battled alcoholism and died of a stroke aged 53. Her sister Anne-Marie, died young.

In her biography she spoke frankly for the first time about being sexually abused as a child.

Asked not long before Anne-Marie's death why she ran, Freeman said: "I've got a sister who has cerebral palsy, and I should make the best use of my arms and legs."

From an early age her drive to succeed was phenomenal, despite being laughed out of class at school when she said her aim was "to win Olympic gold for Australia".

Now, all these years later, she is - as one Australian journalist has said - "Bigger than Shane Warne, Harry Kewell, Dame Edna Everedge, Rolf Harris and Kyle Minogue rolled into one."