By Jane Dreaper
Health correspondent, BBC News
John Suchet is now caring for his wife, Bonnie, after she developed dementia
He has reported on momentous events such as the revolution in Iran, and he's won awards as a newsreader.
Now John Suchet is talking publicly for the first time about one of the toughest events in his life.
Dementia is slowly robbing him of his wife of more than 20 years, Bonnie.
He told BBC News: "I've gone from being a lover to a carer."
She began to develop symptoms of the devastating brain disease in her early 60s, and is now aged 67.
She was diagnosed with dementia three years ago, after sporadic instances of forgetfulness and confusion.
Doctors think Bonnie Suchet has Alzheimer's disease. Her husband prefers to call it "the A word".
'Love and cherish'
Mr Suchet, 64, said: "By and large, her morale is good. She's happy. She smiles at me.
"I should be grateful because she's co-operative most of the time.
"I promised myself after the diagnosis, 'Right, John, you will be an understanding husband - you will love and cherish your wife.'
John Suchet: Our marriage was made in heaven but it has changed so much now
"Life isn't that simple. Every now and then, you just explode.
"It's a culmination of little things - dinner plates going straight back onto the shelf instead of going into the dishwasher or being wiped dry while they were still dirty."
Mr Suchet has been able to air his distress and guilt by meeting regularly with an Admiral Nurse, who is a specialist nurse working with dementia sufferers but particularly their carers.
The nurse, Ian Weatherhead, said: "I first met John and Bonnie two years ago. At that time, he needed a release.
"There was frustration in trying to manage Bonnie's behaviour, and also denial about Alzheimer's disease, and confusion about what it meant.
"John comes to see me down at my office - and sometimes I see him at home, so I can monitor Bonnie and see what's changed for her.
"I've yet to meet a carer who hasn't shouted, sworn or got angry at the person they're looking after - and then felt guilty. Families row. It's a normal part of life.
"And yet people feel so bad about it when they're caring for someone with dementia, because they're exhibiting emotions to someone who can't understand or comprehend what's going on.
"John's a great guy to work with - and being the journalist he is, he takes copious notes on everything we talk about."
Mr Suchet is taking part in a fundraising event in central London, in aid of For Dementia, the charity which funds Admiral Nurses.
He has access to the specialist help because he lives in a part of London where the NHS has paid for eight such nurses.
There are only about 70 Admiral Nurses in England, and one service in north Wales, in Flintshire. Scotland doesn't yet have any.
Mr Suchet said: "There should be 70,000 of them.
The Suchets got married more than 20 years ago
"The best bit of advice Ian gave me was to beat the living daylights out of a cushion every now and then. It works.
"I keep thinking I'm a complete failure and I'm useless at being a carer. But Ian tells me I'm actually doing quite well."
The former ITN correspondent and newsreader is still presenting a daily live quiz show, Going for Gold, on Five.
He told me the work is "good therapy".
He adores classical music and has written five books about Beethoven. All are dedicated to Bonnie.
It is of huge sadness to Mr Suchet that his wife can no longer share what used to be a joint passion.
He said: "We went to every place that Beethoven ever went to that is still there to be seen. She loved it. I loved it.
"But now she looks at the books and she says, 'Bloody Beethoven - I've had enough of him.'
"I have to stop myself from saying, 'You weren't like that before.' I have to remind myself it's not my Bonnie who's talking.
"She's gone. And yet she's physically still there."