The 52-year-old former actress made public her decision to end the relationship spanning 30 years, and marriage of some two decades, in interviews published in the daily Repubblica and La Stampa newspapers.
“I have been forced to take this step, I don’t want to add anything else,” La Stampa Sunday quoted Lario as saying, adding that she had consulted a lawyer.
Last week, Lario publicly lashed out at the 72-year-old Berlusconi over his attitude towards women and his penchant for former showgirls and models.
“Shamelessly trashy” was the way she described her husband’s political party’s selection of women candidates for the European Parliament elections.
She also criticised Berlusconi for attending the 18th birthday party of a woman in Naples, having never attended such parties for any of his own children.
Berlusconi’s lawyer told journalists that the premier had no comment on what was a “strictly personal matter”.
Berlusconi and Lario were married in 1990 and have three children. The politician also has two children from a previous marriage.