Complex sentence: Her twin sister moved to Spain in 1739 to marry Philip of Bourbon, a younger son of Philip V of Spain, and a parting that Henriette regretted greatly, and she withdrew further into her music.
Split into simpler sentences: Her twin sister moved to Spain in 1739 to marry Philip of Bourbon, a younger son of Philip V of Spain. Henriette was despondent about being separated from her twin sister, and she withdrew further into her music.