Well, this is an engagement that should be more accepted than his betrothal to Heather Mills: Former Beatle Paul McCartney has proposed to Nancy Shevell, his girlfriend of four years, People reports from a source. The pair began dating in the Hamptons in 2007. And though they are 17 years apart, People‘s source says age ain’t nothing but a number for the couple. “They have the right chemistry,” says the source. “They’re both cool, chilled out, and optimistic.” McCartney was previously married to model Mills; the rock legend was also married to photographer Linda McCartney for nearly 30 years before she died of breast cancer in 1998.