Talk about a baptism of fire. Only months after Nick Clegg was elected leader of the Liberal Democrats in March last year, he and his wife Miriam found themselves at the centre of a media storm. The cause was his uttering of four little words, “no more than 30”, when asked in an interview with a men's magazine just how many notches he'd carved on his bedpost. Almost six months on, the story might be receding in the public consciousness, but unfortunately for the Lib Dem leader, it's one of those little nuggets that tend to lodge in the brain.

The episode is clearly something that the couple would rather put behind them, but as Clegg embarks on his first party conference as leader in Bournemouth this week, Miriam González Durántez, pregnant with their third child, says of his indiscretion: “It was a jokey response to a cheeky question that was taken out of context and, in my view, blown out of all proportion - probably with a political intention.”

We meet in the 11th-floor office at the law firm DLA Piper's smart London HQ, a stone's throw from St Paul's Cathedral, where she is a lawyer specialising in trade. However, Miriam, 40, insists that nothing that her husband may have said in the GQ interview has changed how she feels about him. “I married Nick because he was the best man I'd ever met,” she says. “And nothing's happened for me to alter my view. Funnily enough, though, I really don't think that the matter would have been an issue in Spain. And you know what? I don't think it should have been an issue here either. But as it happens, I'm not the sort of person to let that sort of thing bother me anyway.”

The public discussion of Clegg's conquests, and the ensuing debate about “how many is too many?”, must all have seemed a long way from Olmedo, the tranquil village 90 minutes' drive northwest of Madrid where she grew up. “It might be just a short drive over the mountains, but it's worlds apart,” says Miriam. “It's very dry, very austere,” she says, adding with a laugh, “like the people.”

It was an idyllic childhood. Her parents were teachers and her father, José Antonio, was also the village mayor. In 1977 he won election to the Spanish parliament as a senator representing the Central Democratic Union, whose leader, Adolfo Suárez, became the first democratically elected Prime Minister after the long years of General Franco's rule.

After leaving school, Miriam took a law course at the university in Valladolid before winning a scholarship to study in Bruges, where she met Clegg in the early 1990s. Was it love at first sight? “He says it was for him,” she says. “As for me, I was trying to help a friend to get close to Nick, and in the process I fell for him. We knew very quickly that we belonged together.” The clincher for Miriam was when Clegg “very bravely” accompanied her to flamenco classes, “because if you see him dancing [flamenco-style], you'd realise that it's not something he'd normally attempt. Afterwards my girlfriends said: ‘This is the man for you'.”

The couple dated for several years when they were both working in Brussels, before Clegg finally proposed. They got married in Spain in 2000. “We had a wonderful party, after a traditional Spanish wedding,” she says. “The British side of the family were terrified to learn that we Spanish partied until 7am. But to my surprise, they saw the night through, and I gave them all hot chocolate in the morning.”

Her only regret is that José Antonio, to whom she was very close, was not there to celebrate. “He died in a car crash in 1996. It was a terrible thing, and living in Brussels at the time made it even worse. The experience of losing someone so close in such a way, and getting the fateful phone call when you're so far away, is something that I wouldn't wish on anyone.”

When Miriam first met Clegg, his political views were still taking shape. “He was a liberal with a small ‘l',” she says. And while José Antonio immediately took to Clegg, she says that she and her father were surprised by his hostility towards Margaret Thatcher. “That surprised us; viewed from Spain, the idea of a woman prime minister at the time seemed so radical. But I now understand why so many of Nick's generation saw her differently.”

Given her own broadly liberal views, she readily supported Clegg's decision to enter politics as a Lib Dem - first winning election as a Euro MP in 1999; then, six years later, to Westminster as MP for Sheffield Hallam. She was just as supportive when he decided to stand for leader: “It was a wonderful opportunity.” Since becoming leader, though, Clegg hasn't been given the smoothest of rides by the press, despite pushing Labour into third place in terms of the popular vote at the local elections earlier this year. “Being the daughter of a politician, I knew what to expect,” she says with a shrug. “You have to take what the press say with a pinch of salt.” Unlike some political wives, Miriam has kept a low profile. Does she think party leaders' wives should stay out of the limelight? “I can speak only for myself, but I have my career and my family to take care of. But, of course, I support Nick 100 per cent; what's important for him is important for me.”

She has had little to do with the other leaders' wives since Clegg was catapulted to the party's top job and says that she is unlikely to pen an overly intimate, Cherie Blair-style memoir: “If I ever write a book, I'd prefer to write fiction rather than something so personal.”

But for all the demands imposed on party political leaders in an era of 24-hour rolling news, Miriam says she and Clegg, who live in Putney, southwest London, have sought to live an ordinary family life for the sake of their sons Antonio, 6, and Alberto, 4. “We juggle the parental duties like every other family with young children,” she says. “But Nick puts a lot of effort into being with the boys as much as possible, and takes them to school every morning.” This weekend Clegg caused a stir when he admitted that he is “a father before a politician” and will consider educating their children privately because of the poor quality of state secondary education.

Miriam and Clegg are looking forward to becoming parents again in the new year: “I'm one of three, Nick's one of four, and we've wanted three kids for a long time, so we're delighted.” And, proud Spaniard that she is, she is determined that their children grow up bilingual. Miriam speaks only Spanish to her sons at home, as does Clegg - even if she gives him only “eight out of ten”.

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