Sources close to Naomi Campbell, 42, say the model has cooled her relationship with Russian billionaire Vladislav Doronin, 50.
Friends say the couple, who have been dating since 2008, have decided to take "a break" after going through a rough patch.
The insider explained the split to the New York Post. "Naomi and Vlad have broken up, and he's been out partying in New York.
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"Naomi and Vlad have a complex relationship, and sometimes break up and make up. In many ways their relationship is like a business arrangement.
"Naomi brings glamour to his hotels and properties, and he treats her extremely well. But they spend a lot of time apart due to work commitments."
Naomi is currently following in the footsteps of fellow models Elle Macpherson and Tyra Banks by mentoring up-and-coming starlets on US series The Face.
Last year, the catwalk queen threw a lavish bash for Vladislav's 50th birthday inside the magnificent 15th century Mehrangarh Fort in Jodhpur, India.
The star wanted only the best for the man she once described as "a sweetie" and "very special".
Naomi and Vladislav became inseparable after meeting at the 2008 Cannes Film Festival. During their union, Naomi became increasingly smitten – and serene.
Their loving, stable relationship had a positive effect on her and newspaper stories of her anger management issues became a thing of the past.