Sean Sasser, whose relationship with the late Pedro Zamora on MTV's "The Real World: San Francisco" broke cultural barriers on U.S. television, has died, his longtime partner told CNN on Thursday. Sasser was 44. Sasser, who had been HIV positive for 25 years, died Wednesday from mesothelioma, a rare form of lung cancer that was diagnosed just last month, Michael Kaplan said. He died in the Washington home he shared with Kaplan. Sasser was not one of the original cast members but became a household name as his relationship with Zamora was explored during the show's third season in 1994....