Is concealing a past sin of adultery from one's husband considered a betrayal of him, and must he be informed of it or not?

Do not tell your husband about the illicit acts you committed, and conceal yourself; for the Messenger of Allah, peace and blessings be upon him, said: "O people, it is time for you to desist from transgressing the limits of Allah. Whoever commits any of these abominable deeds, let him conceal himself with the concealment of Allah, for whoever exposes his misdeed to us, we will apply the Book of Allah upon him." As long as you have repented with a sincere repentance, there is no reason for your fear and distress, for repentance erases what came before it. So, turn away from these whispers and think well of your Lord.