Langevin married Jeanne Desfosses in 1898, on his return from Cambridge. By 1904 the family had grown to include two sons, Jean and André, and a daughter Madeleine. Hélène followed in 1909. Langevin was part of an intimate circle of friends, known as the “Arcouest group” from the location of their family holidays, which included the Curies, the Perrins and the Borels. As parents they also combined their efforts in educational support for their children. The Langevin marriage was stormy. A few years after the premature death of Pierre Curie, Langevin developed an intimate relationship with Marie Curie. When their love affair became public in 1911, salacious press reports vibrated through the international scientific community. Langevin challenged the journalist Téry to a duel. The scandal caused huge distress and led to Langevin living separately from his family. His return to the marital home after the war did not prevent him having another liaison.