Prince William wished mum Princess Diana had met Kate Middleton on his wedding day. The royal candidly opens up in “The Jubilee Queen with Katie Couric,” airing tonight at 9 p.m. on ABC, about missing his mother the day he walked down the aisle. “I sort of prepared myself beforehand,” the prince tells Couric, “[but] it’s the one time since she’s died where I’ve . . . thought to myself it would be fantastic if she was here, and just how sad really for her, more than anything, not being able to see it.”