/and at first she restrained him when the fire of his heart grew too hot; but his later deeds grieved her/
After marrying Fëanor, Nerdanel bore him seven sons: Maedhros, Maglor, Celegorm, Caranthir, Curufin, Amrod and Amras. Nerdanel, unlike her husband, was of a peaceful nature and sought to moderate his fiery temper and pride with wisdom. For a time, she was the only one able to influence him.
Nerdanel refused to follow her husband to Middle-earth and their parting was not a happy one. When it became clear that he intended to leave Valinor for good, she came to him and pleaded with him to let her youngest sons, Amrod and Amras to remain with her. Fëanor would hear nothing of it and accused her of being against him and in league with the Valar, namely Aulë. He said if she did not follow him she would be abandoning all of their children. She scorned him saying that he would not have them all and then she left, possibly retiring to her father’s house where she apparently still lives in Aman.
By refusing to join her husband in revolt, she herself avoided the Doom of Mandos but her sons did not. The last remnant of her family survived through her grandson Celebrimbor, the forger of the three Elven Rings of Power.
While still in early youth Fëanor wedded Nerdanel, a maiden of the Noldor; at which many wondered, for she was not among the fairest of her people. But she was strong, and free of mind, and filled with the desire of knowledge. In her youth she loved to wander far from the dwellings of the Noldor, either beside the long shores of the Sea or in the hills; and thus she and Fëanor had met and were companions in many journeys. Her father, Mahtan, was a great smith, and among those of the Noldor most dear to the heart of Aulë. Of Mahtan Nerdanel learned much of crafts that women of the Noldor seldom used: the making of things of metal and stone. She made images, some of the Valar in their forms visible, and many others of men and women of the Eldar, and these were so like that their friends, if they knew not her art, would speak to them; but many things she wrought also of her own thought in shapes strong and strange but beautiful.
‘For Fëanor was driven by the fire of his own heart only, working ever swiftly and alone; and he asked the aid and sought the counsel of none that dwelt in Aman, great or small, save only and for a little while of Nerdanel the wise, his wife.’ - Of Fëanor, The Silmarillion.