Complex sentence: McDowell's partner was theatre historian and director Laurence Senelick, whom he met in 1969 when McDowell was a cast member of the Senelick-directed play, "Bartholomew Fair".
Split into simpler sentences: McDowell's partner was theatre historian and director Laurence Senelick. McDowell and Senelick, whom he met in 1969 when McDowell was a cast member of the Senelick-directed play, "Bartholomew Fair".