They have been called the first couple of Northern Ireland politics. He is often stern and famously buttoned-up; she has been described as “fire and brimstone in a Laura Ashley package”.
Peter Robinson concentrates on being First Minister in the Northern Ireland government, having abandoned the rhetoric of a lifetime to work alongside Sinn Fein ministers he denounced for decades as terrorists and gunmen.
His wife Iris, meanwhile, has majored in the politics of old-time religion, declaring that a government has a responsibility "to uphold God's law morally" and branding homosexuality as a sin. That last comment caused gay groups to call her "UK Bigot of the Year" and the "wicked witch of the north".
But on Wednesday, Peter made the dramatic and emotional announcement that his wife had attempted to kill herself after indulging in an affair with another man. And last night a BBC report claimed that Iris had broken the law by not declaring a financial interest in a business deal. It is alleged that she obtained £50,000 from two property developers which was then paid to her young lover to help him set up a cafe.
The people of Northern Ireland are agape at the details which have emerged: that Iris, while depressed, gave support to a young man who had suffered a family death. She explained: "I encouraged friends to assist him by providing financial support for a business venture. Regrettably, the relationship later developed into a brief affair. It had no emotional or lasting meaning."
She said that, racked by guilt and shame, she had attempted to kill herself last March. This means that for 10 months her husband Peter has been grappling, in secret, with the personal and political implications of the hugely unsettling events.
He appeared on television on Wednesday night, exuding anguish and pain, to say he was devastated but had decided to forgive her after she begged his forgiveness in a spirit of humility and repentance.
"My immediate impulse was to walk away from my marriage," he said sorrowfully. "I felt betrayed after almost 40 years of being happily and closely bonded together."
He delivered much of his script directly to camera, hunched in a chair, his voice close to breaking. This was a new, unknown Peter Robinson, the cold fish replaced by a vulnerable human being.
Previously he had employed two familiar modes of presentation: one would involve scathing and sometimes contemptuous attacks on opponents. Belfast politics is a rough business, and he has been one of its more pitiless practitioners.
The other side of him was what former Northern Ireland Secretary Peter Hain once characterised as a formidable politician with a forensic mind and tremendous ability.
These two modes have alternated during a long and eventful career. But on show now is a third and completely unfamiliar Robinson persona – that of a man who has been deeply hurt. He is engaged in salvaging two enterprises with which he has been obsessed for 40 years: his marriage and his career.
He is the second leader of the Democratic Unionist party, having taken over from the Reverend Ian Paisley, the nearest thing to a modern-day Old Testament prophet, famous for his fundamentalist Protestantism. The Iris affair is thus the perfect storm for the Robinsons, a nightmarish vortex of the political, personal and theological.
With a Westminster election looming, the whole affair is bound to have political impact, as the DUP seeks to fend off rivals for the unionist vote. But the shock of the revelations is so great that, as yet, its overall implications remain unclear.
Huge as the impact has been, the widespread belief is that there may be more disclosures to come. So far, statements from Peter and Iris have concentrated on her depression, her affair and her suicide attempt.
They have dealt only glancingly with the question of the couple's finances, which has also been the subject of much rumour. Asked about his finances, the First Minister replied: "In all of my public life I have acted in the most professional and ethical way. There is nothing that anybody will produce. I am absolutely certain that everything that I have done has been done as it should. I have heard all sorts of nonsense and rumours over the last number of days, even indicating that I had lost three million pounds in shares and a lot of other stuff. Absolute rubbish."
He has said he is determined to stay on as First Minister, and the signs so far are that what has emerged to date will not eject him from office. But his survival ultimately depends on a clean bill of financial health, with satisfactory answers to whatever money questions are raised.
Certainly anything that caused him to step down as First Minister would spark a full-blown crisis for Northern Ireland's fledgling devolved administration, given that over the past year it has seemed increasingly fragile.
Peter has been a familiar figure in politics for years, though always in the shadow of Ian Paisley, whom he began by hero-worshipping. He went on to become Paisley's brilliant back-room boy, his organisational and election skills complementing his leader's rhetoric.
He has gone through extreme and moderate phases. At one period of high tension in 1987, he took part in an incursion by hundreds of loyalists into the Irish Republic, intended to demonstrate weaknesses in border security. But ignominiously he was arrested by southern police; and even more ignominiously he agreed to pay a £15,000 fine. The more extreme loyalists abandoned him after this, regarding his performance as craven.
There were other times when he was associated with sinister loyalist elements, at one stage donning a red beret, at another speaking of times when "legitimate force" was justified. Pronouncements such as these led a one-time head of the Northern Ireland civil service to describe him as "somewhat scary".
But on other occasions he was viewed as more pragmatic, with British ministers trying to coax him to take a more moderate line than Paisley. One of these, the former Northern Ireland Secretary Douglas Hurd, recalled: "At one time I had hopes of Paisley's young deputy Peter Robinson, who had a sharper mind.
"I invited him to dine alone with me in the hope that hospitality would unlock a closed spirit. He accepted, but would not touch wine or whisky and I got nowhere."
Iris, at first a quiet and dutiful wife, gradually made her way into politics, Peter helping her to become mayor of the local council he dominated. In 2001 she became MP for Strangford, a constituency next door to her husband's.
Earlier, the family's reputation had been damaged after it was disclosed that its members earned hundreds of thousands of pounds annually in salaries and expenses (all of the arrangements were perfectly legal). The money was amassed because Peter and Iris were both Westminster MPs and members of the Belfast Assembly, and because they employed their offspring.
This earned them the damaging nickname of "Swish Family Robinson". The family was the focus for harsh criticism locally after it emerged that they had claimed a total of £30,000 for food while attending parliament over a four-year period.
Ironically, given Iris's anti- homosexual stance, one of the couple's sons was pictured on the internet last year apparently kissing another man at a party. A newspaper later clarified that the embrace was "just part of a night of high jinks among a student gathering".
Iris has made remarks which seem to indicate a low self-esteem, once telling a political meeting: "I don't pretend to be anything other than a simple housewife."
She can also appear to be touchingly naive when giving newspaper interviews. On one occasion she declared: "I recognise I'm not the brightest light in the chandelier when it comes to debating constitutional issues. I leave those to Peter."
In one interview, she said she was annoyed at long-standing rumours that her husband beat her. "This malicious lie was started by the British government in an attempt to blacken Peter's name when he was protesting at the Anglo-Irish Agreement," she complained. "It took root because I was in hospital 17 times during that period with gynaecological problems."
But the Swish Family Robinson jibe has particular resonance because of the couple's impressive home, on which Iris has lavished much money, packing it with expensive features and hundreds of ornaments. They are currently supervising the construction of an even-more-opulent house in the hills overlooking Belfast, and have a holiday home in Florida.
For many months, Peter has been curiously inactive as First Minister, holding back on moves to devolve policing powers to Northern Ireland in a way which has puzzled most at Stormont. The most frequently advanced explanation for this was that he was, as Sinn Fein claimed, "spooked" by the fear of losing seats to hardline opponents in the Westminster election.
But now, an alternative explanation is emerging: he has been grappling not just with political complications but with personal ones – struggling to deal with the behaviour of his colourful wife.