“By mutual agreement, we have decided to put our marriage on hold,” the couple said in a joint statement sent to Spanish news agency EFE, without specifying if they would divorce.
“Our commitment to our children remains intact. Since it is a private decision, we ask for the utmost respect from all those around us.”
Last week, gossip magazine Lecturas published pictures of Urdangarín, who was released on parole in 2019, walking hand-in-hand with another woman on a beach in the south of France.
Spanish media later identified her as Ainhoa Armentia, who works with Urdangarín at a law firm in the northern Spanish city of Vitoria.
Asked about the photos on Thursday, Urdangarín told reporters it was “a difficulty which we will manage with the utmost calm, as we have always done.”
Princess Cristina, 56, and Urdangarín, a 54-year-old former international handball player and Olympic medalist with Spain, have been married for over 24 years and have four children.
A Spanish court in 2017 found Urdangarín guilty of taking millions of euros between 2004 and 2006 from a non-profit foundation he headed in the island of Majorca.
He served part of his five-year and 10-month sentence for embezzlement and tax evasion until judges in 2019 allowed him to swap it for community work.
Cristina, who lives in Switzerland, herself was also tried on charges that she helped her husband evade taxes, but was acquitted.
During the trial, she repeatedly denied knowing anything about her husband’s business affairs.
Cristina was the first member of Spain’s royal family to face criminal charges since the monarchy’s restoration in 1975.
The couple have been excluded from all of the royal family’s official public appearances since late 2011.
King Felipe VI stripped his elder sister Cristina of the title of duchess in 2015, a year after he ascended to the crown following his father Juan Carlos’ abdication in 2014.
Juan Carlos left Spain in August 2020 to live in self-imposed exile in the United Arab Emirates in the face of mounting questions over his finances.