Mr Berlusconi says he does not believe his marriage can now survive
Silvio Berlusconi has demanded an apology from his wife after she accused him of "consorting with minors" and said she wanted a divorce.
The Italian prime minister, 72, told the Corriere della Sera that he did not think their marriage could survive.
Veronica Lario spoke out after her husband attended the 18th birthday party of a friend's daughter.
She has also clashed with her husband over his choice of inexperienced but attractive female election candidates.
"Veronica must apologise publicly - and I don't know if that will be enough," Mr Berlusconi said in an interview with the Italian daily newspaper.
"It is the third time she has done this to me in the middle of an election campaign. It's too much," the billionaire prime minister said.
Asked whether his 19-year marriage to Ms Lario could survive, he added: "I don't think so. I don't know if I want it to this time."
He insisted he had done nothing wrong and said his wife had been unwittingly misled by the media.
"Veronica has believed many inaccurate things written in the press, unfortunately," he said.
La Stampa newspaper quoted Mr Berlusconi as saying he had handed the matter over to his lawyers and that his wife's comments might even warrant legal action.
"To tell the truth, there may even be conditions to sue for defamation, but it's best to leave that alone," he said.
The row began last week when Ms Lario, a 52-year-old former actress, wrote an open letter complaining about her husband's choice of young, attractive female candidates - some with little or no political experience - to represent his Freedom Party in June's EU elections.
But the final straw came when Ms Lario read that Mr Berlusconi had attended the 18th birthday party of the daughter of one of his business associates.
The teenager is reported to be an aspiring TV starlet from Naples who calls the prime minister "Daddy".
Mr Berlusconi was reported to have bought her a golden necklace studded with diamonds as a present.
"That's enough, I cannot remain with a man who consorts with minors," Ms Lario was quoted as saying in La Repubblica.
Won third term as prime minister in 2008
Fought off a series of corruption and fraud charges
Private fortune estimated at $6.5bn (£4.4bn)
Owner of AC Milan football club
"I read in the papers about how he has been hanging around a minor - because he must have known her before she was 18 - and how she called him 'Grandpa' and about their meetings in Rome and Milan.
"This is no longer acceptable. How can I stay with such a man?" La Stampa quoted her as saying.
She also said Mr Berlusconi had failed to attend his own daughters' 18th birthday celebrations.
The BBC's David Willey, in Rome, say the spat between Mr Berlusconi and his wife is filling the pages of Italy's newspapers.
Even one of Mr Berlusconi's political allies, Umberto Bossi, is quoted as saying "if I had a starlet as a girlfriend, my wife wouldn't let me back into the house!".
The current dispute is not the first time Mr Berlusconi and Ms Lario have aired their differences in public.
In 2007, Mr Berlusconi issued a written statement apologising to his wife for flirting with other women after she demanded a public apology.
Ms Lario is Mr Berlusconi's second wife. The couple have three children, all in their 20s.