La dame en souspirant (фемслэш)

Five years into her marriage, Irulan was... unhappy. To say she had merely run out of endurance would be inadequate; were that true, she would have been upset earlier. The truth was obvious, though Irulan continued to skirt around it as long as she could. What had changed these past years was her relationship with Chani.
--
Irulan strays from the Bene Gesserit not for Paul, but for the kindness and love of his concubine.