Sometime after a contract was signed on 11 December 1254, she married John I, Count of Blois of the House of Châtillon.

She brought as her dowry her titles of Pontarcy and de Brie-Comte-Robert, which had been named after her ancestor Robert I of Dreux.

[citation needed] The marriage produced one child, a daughter Jeanne, who was heiress to her father's title and estates.

Alix and John founded several religious houses including the Monastery of La Guiche near Blois in 1277.

Her daughter, Jeanne, who was the suo jure Countess of Blois had married Peter, Count of Perche and Alençon, a son of King Louis IX of France and Margaret of Provence.