The rock 'n' roll icon has been spotted with U.S. heiress Nancy Shevell, Hollywood actress Rosanna Arquette and former Olympic horsewoman Tanya Larrigan in recent weeks.
"I think he's got three different girlfriends, so I wish all the girls the best of luck. Well, better them than me," The Daily Telegraph quoted Mills as saying on the British television program "GMTV."
Mills and McCartney officially ended their four-year-long marriage in court last month, with Mills walking away with nearly $50 million in cash and assets.
Mills also talked on "GMTV" about how she doused McCartney's lawyer Fiona Shackleton with water at the courthouse.
"Mrs. Shackleton said something under her breath, so I cleansed and baptized her. I thought she looked fantastic -- I thought it did her the world of good," Mills said.
"And now I've been offered lots of jobs for creating re-looks for women of her age with those kind of hair-dos. So I have no regrets."