Is the husband considered sinful if he does not inform his first wife of his marriage to another woman, knowing that his not informing her stems from his desire to preserve the stability of his life with both wives?

Allah has permitted a man to have multiple wives, provided he is able to be just among them, for Allah Almighty says: "Then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one" (An-Nisa: 3). The husband is not required to inform his wife of his desire to marry a second wife, and it is appropriate to consider what is best in this matter.