Osbourne's online statement came after TMZ reported Monday he and Sharon, his wife of 31 years, had split up and were living separately in Los Angeles.
"For the last year and a half I have been drinking and taking drugs," Osbourne, 64, wrote on Facebook. "I was in a very dark place and was an [expletive] to the people I love most, my family.
"However, I am happy to say that I am now 44 days sober. Just to set the record straight, Sharon and I are not divorcing. I'm just trying to be a better person," he added. "I would like to apologize to Sharon, my family, my friends and my band mates for my insane behavior during this period ... and my fans."