Mary-Kate Olsen and Olivier Sarkozy had a romantic dinner at Antica Pesa in Williamsburg on Tuesday. The diminutive designer and her 16-years-senior beau were “very affectionate,” a spy said, adding they were “holding hands, kissing and openly showing their affection.” Sarkozy did the ordering for the duo during their two-hour dinner of Italian pasta and vino. The couple, who were often spotted snuggling together at Knicks games last season, have been dating since last May.