What is the theme in The Idiot by Fyodor Dostoevsky?

Love and marriage is another theme. In the novel, there are three love triangles. First, Ganja fights Rogozhin for the hand of Nastassya. Secondl Natassya falls in love with both the Prince and Rogozhin. Third, the Prince finds it difficult to choose between Aglaya and Natassya. In the end, all three love triangles prove destructive. Ganja loses a lot of his pride and confidence; the Prince goes insane; the police imprison Rogozhin for murdering Nastassya and Aglaya runs off with a Polish count.