Mindy McCready has said her only addiction is violent relationships, including the one with longtime boyfriend Billy McKnight. The '10,000 Angels' singer has had drug problems since 2004, which is when she was convicted on prescription drug fraud charges. In May of 2005, she was arrested for driving under the influence of alcohol, and she's continued to battle alcohol and Oxycontin in the years since, leading up to her appearance on VH1's 'Celebrity Rehab With Dr. Drew.'