What is theme of the forsaken merman?

The theme of "The Forsaken Merman" by Matthew Arnold centers on the tension between love and the inevitability of loss. It explores the deep longing of the merman for his human wife, who ultimately chooses her human life over their underwater existence. This theme reflects broader ideas of alienation, the clash between different worlds, and the sorrow that arises when love cannot bridge those divides. The poem poignantly captures the merman's despair and the melancholic beauty of unfulfilled love.