Complex sentence: He had a reputation for the "rock and roll lifestyle" during Ratt's heyday, and he was a habitual heroin user for some time; allegedly it was Motley Crue bassist Nikki Sixx who introduced him to the drug in Ratt's earlier days.
Split into simpler sentences: He had a reputation for the "rock and roll lifestyle" during Ratt's heyday, and he was a habitual heroin user for some time. Allegedly it was Motley Crue bassist Nikki Sixx who introduced him to the drug in Ratt's earlier days.