Complex sentence: At the time of the film's creation, David De Mering was the personal secretary and alleged lover of fellow cast member Bunny Breckinridge; his inclusion in the cast was probably a result of this association.
Split into simpler sentences: At the time of the film's creation, David De Mering was the personal secretary and alleged lover of fellow cast member Bunny Breckinridge. His inclusion in the cast was probably a result of this association.