Could Jack Nicholson's May-December romances be over, on screen at least? The lothario -- who dated Helen Hunt in ''As Good as It Gets'' and Lara Flynn Boyle in real life -- is paired with women near his age in ''About Schmidt.'' In the film, the 65-year-old is married to June Squibb, 67, and hot-tubs with a naked Kathy Bates, 54. And in an untitled film shooting later this year, he'll send up his own image and fall for Diane Keaton, 57, who plays the mom of trophy girlfriend Amanda Peet. ''It may be surprising for people, but it's highly refreshing,'' says ''Schmidt'' costar Howard Hesseman. ''There comes a point in the lives of all great actors where you act your age.'' Meanwhile, don't even raise the issue with Bates. ''Did you just call me a 'senior woman'?'' she snapped at the film's L.A. premiere. ''All this stuff about age is bulls---!''