Complex sentence: Constant became bored with Germaine because of her constant need for attention and in 1809 he secretely married a woman who had been divorced twice, Caroline von Hardenberg, (related to Novalis and Karl August von Hardenberg).
Split into simpler sentences: Constant became bored with Germaine because of her constant need for attention. In 1809 he secretely married Caroline von Hardenberg, a woman who had been divorced twice, (and related to Novalis and Karl August von Hardenberg).