McCartney (left) and Mills
RICHARD JENNINGS/PN NEWS/LFI; Retna
07/29/2006 AT 01:00 PM EDT
Paul McCartney has finally filed for divorce from his estranged wife Heather Mills McCartney, according to British news reports. The former Beatle is allegedly citing unreasonable behavior, but his wife of four years is vowing to fight the case vigorously in both Britain and America.
"Heather's going to be filing her own counterclaims about matters both in this country and America," her U.K. rep tells PEOPLE. Because there is no pre-nuptial agreement, at stake is a share of the 64-year-old musician's fortune – estimated to top $1.5 billion – along with the custody of their 2-year-old daughter, Beatrice.
A McCartney insider told the Daily Mirror that the couple split last May because of Mills' "unreasonable behavior," which included being "rude to the staff" and "argumentative".
The rep for Mills, 38, refuses to comment on claims about her conduct. "Any view she has on her divorce will be handled discreetly. She does not feel the need to repudiate claims that she may be headstrong or feisty," he tells PEOPLE.
He adds: "We have no way of knowing if he filed for divorce."
A rep for McCartney declines to comment on either grounds for divorce or if in fact papers have been filed in London, but friends of McCartney say he simply wants a "clean break". He was photographed in his hometown of Liverpool on July 28 and, significantly, was not wearing his wedding ring.
In Britain, once documents are filed, the quickest a marriage can be dissolved is six weeks. However, with his wife's insistence on counterclaiming, it is going to be a long and winding road to a financial settlement – then divorce.
"It's a battlefield and it has become mind-boggling, not just because of Paul's fame but because of the constant stream of stories," says a long-term friend of the musician. "But now with Heather announcing she is prepared to fight, things are just going to get uglier."