What I most admired about Susan Tsvangirai was that she knew that the success of your family was dependent on the success of your country. She never moaned about what life was like for her and her children and the risks that came from living with Robert Mugabe's nemesis. It was always about the children of Zimbabwe. It was a typical caring and motherly attitude that Zimbabwe had always wanted from its First Lady but never got.

She was a total contrast to Grace Mugabe. Where Grace was known for her extravagance, her shopping sprees, her love of designer labels, Susan was an ordinary woman who wore ordinary clothes and lived an ordinary lifestyle. When Morgan Tsvangirai won the first round of the presidential elections last year, and looked poised to oust Mr Mugabe, people flocked to Susan offering to groom her for her new role, remodel her hairdo and update her wardrobe. She was actually annoyed by these overtures, these attempts to curry favour.

I visited the Tsvangirais several times before I was forced to flee from Zimbabwe. They lived in a simple three-bedroom house – a far cry from the multimillion-dollar Mugabe mansion. Whenever you were in their company, you got this sense of a perfect union. On one occasion in 1997 – after her husband had survived an attempt to throw him out of a 10th-floor window – Susan was tenderly changing his bandages. Her love and affection was very touching.

She was not part of the political machine, and bar the odd appearance at party rallies, she preferred to stay out of the limelight, but their commitment to each other was never in doubt. For a woman who lived with death threats, intimidation by security forces and a string of attempts on her husband's life, she kept an impeccable sense of calm and never forgot the importance of good humour.

During the third treason case against Morgan in 2007, his wife confided: "Look, it's difficult for me, but I have no choice but to support the cause my husband is fighting for." It was the cause she believed in and she thought her husband was doing the right thing. If it was not for her support, it would have been very difficult for Morgan to remain engaged.

He once said that the best decision he had made in his life was to marry Susan. Her death is going to devastate him. He's a very strong character, he has felt first-hand the worst that repression can offer, and he bears innumerable scars of his struggle against Mugabe.

But this is going to crush him. I just cannot imagine the pain and hurt that he's going to feel, and it is going to make his already difficult task of being Prime Minister even harder.