Jerry Seinfeld will not be hosting “The Marriage Ref,” the new NBC show he’s executive-producing, even though the network wanted him to. “NBC is desperate for a hit, and they really wanted Jerry to host the show,” our source says. “They went back and forth with him for months, but he wouldn’t budge.” Seinfeld’s rep, Elizabeth Clark Zoia, says, “Jerry handpicked Tom Papa to be the ‘Marriage Ref’ from the inception. He is extremely enthusiastic about his hands-on role as executive producer.”