Heather Mills has accused estranged husband Sir Paul McCartney of cheating on her with US millionairess NANCY SHEVELL. The former Beatle has reportedly been seeking comfort in the arms of Shevell, following Mills' public outbursts on U.S. and U.K. TV last week (ends02Nov07). The pair were photographed out and about in the Hamptons area of New York last week (ends02Nov07), where they have been seen holding hands and enjoying romantic late-night dinners. And the images have prompted Mills to accuse MCCartney of committing adultery. Mills' U.S publicist Michele Blanc says, "She did ask him if this was going on while they were together and Paul swore that it did not happen then and that she was a friend." Shevell is the 47-year-old wife of New York Port Authority commissioner Bruce Blakeman, and is a well-known New York socialite. MCCartney has been separated from Mills since May 2006, but is currently embroiled in a bitter divorce battle with the ex-model.