Complex sentence: He entered an alcohol and drug rehabilitation program, became clean and sober for the first time in years in August 1978 and was eventually remarried to his longtime girlfriend, Arlie Litvak.
Split into simpler sentences: He entered an alcohol and drug rehabilitation program, becoming clean and sober for the first time in years in August 1978. Additionally, he was eventually remarried to his longtime girlfriend, Arlie Litvak.