“THE Hills” honey Heidi Montag needs to rethink her relationship with boyfriend/manager Spencer Pratt - again. The two ended their engagement last month, but were spotted shopping for rings (above, with ring inset) in LA Wednesday afternoon. But that night, Pratt was already eyeing other women. Spies at the “Cloverfield” premiere saw him leave Montag’s side “to ask for another girl’s number . . . She turned him down. And Heidi” - who was busy posing for paparazzi - “was ...