Sa'id bin Abi Hnd سعيد بن أبي هند الفزاري · The Chapters on Marriage

"This Verse 'And making peace is better.' was revealed concerning a man who had been married to a woman for a long time, and she had given birth to his children and he wanted to exchange her (for a new wife). She agreed that he would stay with her (the new wife) and would not give her (the first wife) a share of his time. (i.e.) not spend the nights with her)."