VATICAN CITY: The Vatican issued new guidance reaffirming that Catholics are expected to marry only one spouse for life, underscoring Church teaching against polygamy and other multi-partner relationships.

The decree, approved by Pope Leo and released by the Vatican's doctrinal office, urges the Church's 1.4 billion members to seek a single, lifelong partner and avoid multiple sexual relationships.

The document singles out polygamy in parts of Africa, including among some Catholics, and reiterates the Church's longstanding view that marriage is a permanent union between one man and one woman. It does not address same-sex relationships.

The decree describes marriage as possessing "richness and fruitfulness" and says the institution requires fidelity and exclusivity.

"Every authentic marriage is a unity composed of two individuals, which requires such an intimate and totalising relationship that it cannot be shared with others," it says. "Since (marriage) is a union between two people who have the same dignity and the same rights, it demands exclusivity."

Questions around enforcing Catholic teaching on marriage were debated at two Vatican synod meetings in 2023 and 2024, convened by the late Pope Francis, where bishops discussed issues ranging from polygamy to the growth of polyamorous relationships in Western countries.

"Polygamy, adultery, or polyamory are based on the illusion that the intensity of the relationship can be found in a succession of faces," the new decree says.

While reiterating that the Church does not recognise divorce because marriage is considered lifelong, the decree notes that Catholics may seek an annulment to determine whether a marriage was validly contracted. It also stresses that the Church does not expect people to remain in abusive relationships.