Boo and I have been mourning all day. Sean Sasser, AIDS activist extraordinaire, has died at age 44. Sasser entered the American consciousness as Pedro Zamoraâ€™s boyfriend on MTVâ€™s The Real World: San Francisco, back in the early 1990s. Zamora passed away not long after the show ended, due to complications of the disease â€” some say the stress of the filming process led to his deterioration in health at a time when HIV medications were much less effective than they are today. Sasser lived on, working for numerous political and social organizations and becoming a well-known AIDS activist in his own right. According to his life partner, Michael Kaplan, Sasser died of mesothelioma, a rare cancer of the lungs.