Is marriage to a specific person predestined before the creation of man, and can what God has written be changed, and is a suitor leaving his fiancée without return predestined by God?

Marriage is predetermined and inscribed in the Preserved Tablet fifty thousand years before the creation of the heavens and the earth. However, the servant does not know this decree until after it occurs. Therefore, one must take the necessary means and rely upon Allah, for the Prophet, peace and blessings be upon him, said: "Act, for everyone is facilitated for that for which he was created."