Complex sentence: The themes of "Reflections" are similar to those in "The Eolian Harp" as they discuss the same location and both poems describe Coleridge's relationship with his wife and feelings of sexual desire.
Split into simpler sentences: The themes of "Reflections" are similar to those in "The Eolian Harp". They discuss the same location and both poems describe Coleridge's relationship with his wife and feelings of sexual desire.