Is marriage predestined like sustenance, meaning that one will only marry whom Allah has decreed for them, or does predestination mean Allah's prior knowledge and that the matter is by the choice of the spouses, and is the name of the husband or wife written before a person's birth?

The belief of Ahl al-Sunnah (definition) wa al-Jama'ah is that everything that happens to a person in the universe, such as sustenance, a spouse, health, and illness, is predetermined and written, and nothing occurs except by the decree and will of Allah. Allah's knowledge and writing of this does not contradict the servant's will and choice, for the servant has ability and will, but these are not independent; rather, they are under Allah's power and will.