Pope Francis says that it may be acceptable, or even "morally necessary", for married couples to split up if they are at war with each other.
The head of the Roman Catholic Church, an organisation that has traditionally been implacably opposed to divorce, said there was even greater justification for separation in cases where the wife was being abused by her husband.
The Pope made the remarks ahead of a crucial bishops' conference, or synod, in the autumn in which contentious issues such as whether to give communion to remarried divorcees will be discussed by the Catholic hierarchy.
"There are cases in which separation is inevitable," the Argentinian pontiff said during his weekly general audience in St Peter's Square.
"Sometimes, it can even be morally necessary, when it's about shielding the weaker spouse or young children from more serious injuries caused by intimidation and violence, humiliation and exploitation, neglect and indifference."
He acknowledged that separation and divorce had created many "so-called irregular families, even if I don't like this word".
The Church, he said, needed to work out how best it could help people in such situations, and in particular to seek ways to avoid children becoming "hostages of daddy or mummy".
The Pope has shown a more inclusive, compassionate approach to issues such as divorce and homosexuality since being elected two years ago, though he has stopped short of introducing any doctrinal changes.
Liberals within the Catholic Church are hoping for a further shift of stance at the three-week-long synod in October, when bishops from around the world will gather in Rome.
But the Vatican released a working paper earlier this week which suggested that reformists will be disappointed.
The document, a sort of road map that sets out the key topics to be debated, indicated that there would be no change to the current ban on receiving communion for Catholics who had divorced and then remarried.
In the eyes of the Church, their divorces are not valid and they are therefore living in sin with their new partners in adulterous relationships.