Complex sentence: Sellers's difficulties in getting his film career to take off, and increasing problems in his personal life, prompted him to seek periodic consultations with astrologer Maurice Woodruff, who held considerable sway over his later career.
Split into simpler sentences: Sellers's difficulties in getting his film career to take off were compounded with increasing problems in his personal life. These troubles prompted him to seek periodic consultations with astrologer Maurice Woodruff, who held considerable sway over his later career.