Donald Rayfield at Literary Review:
At the heart of The Europeans is an extraordinary ménage à trois. The novelist Ivan Turgenev was for two-thirds of his life in love with the singer and composer Pauline Viardot, wife of the entrepreneur and connoisseur Louis Viardot, who accepted Turgenev as a friend and shooting companion. The relationship (briefly a ménage à quatrewhen Pauline and Charles Gounod fell in love) was sustained by the emotional intelligence of all three and by the balance of interests. They were voluntary exiles (Louis was French, Pauline was Spanish and Turgenev was Russian) who spent much of their lives in Germany, notably in Baden-Baden. Turgenev left Russia, returning only for short visits, to escape police surveillance and to avoid critics outraged by the either too radical or too reactionary protagonists of his novels. Pauline and her husband were abroad largely because of her career as an opera singer.
more here.