CAN THIS MARRIAGE BE SAVED? Try as they might, Jessica Simpson and Nick Lachey weren't convincing anyone of the happiness of their marriage when they stepped out at the Genetic Denim launch party in L.A. the other night. A Lowdown spy at nightclub LAX reports: "They posed for photos together, but there was not much talking. She was sitting on one side of their booth, talking to Eva Mendes the whole time, and he was on the other, hanging out with his bodyguard." The spy adds that although the likes of Cameron Diaz and Justin Timberlake, Lindsay Lohan, Nicole Richie, Prince, Chris Rock, Jeremy Piven, Elisha Cuthbert and Wilmer Valderrama showed up, "Everyone was whispering and looking at Nick and Jessica." .