The Russian oligarch, 50, best known as the owner of Chelsea football club, revealed yesterday that that he is breaking up with his third wife, 36-year-old art collector Dasha Zhukova.
It was claimed this afternoon that the pair's split came after they argued over their plans for New Holland, an island they took over in the centre of St Petersburg.
The couple planned to turn the island, which is separated from the rest of the historic city by three canals, into a tourist attraction, but had very different dreams for how it would turn out, entrepreneur Anton Vuima said.
They have reportedly been living 'separate lives' since Christmas, with Dasha being photographed holidaying with US socialites in the Hamptons, while Abramovich attended events in Russia alone.
Rumours swirl in Moscow over whether Zhukova had already been paid off by her older husband - who is worth an estimated £7billion - or whether lawyers are quietly gearing up for what would be one of the biggest divorces in history. 'Abramovich bought it and they found it hard to divide it. Daria wanted a disco place there, in open air Ibiza style.
'But Roman wanted to build a cultural centre, restaurants and create a kind of a small Europe, which is what happened in the end.
'They argued really badly over it, even in public in New Holland. It happened three or four times.'
It followed claims by Russian society blogger Elena Miro that famously private Abramovich and Zhukova had already organised a secret divorce deal back in May.
Moscow lawyer Dmitry Golobolev estimated that Zhukova could get between 200 to 300 million dollars, a fraction of her husband's estimated wealth.
In a joint statement yesterday, the couple said: 'After ten years together, the two of us have made the difficult decision to separate, but we remain close friends, parents and partners in the projects we developed together.'
The peaceful tone of the statement suggests there will be no court cases with legal arguments over money, Russian family lawyer Georgy Tyurin told Russia's Kommersant newspaper.
'I think that it will be one of those so-called 'civilised divorces', without scandals, without dirty linen washed in the media and without division of jointly earned assets,' he said.