The person:

• who was your spouse at the end of that day and from whom you were not living separate and apart at that time because of the breakdown of your relationship. If, on December 31, 2023, you and your spouse were separated because of the breakdown of your relationship and your separation lasted fewer than 90 days, you are considered to have had a spouse on December 31, 2023; or
• who was your spouse at the time of his or her death in 2023, provided you and your spouse had not been living separate and apart for 90 days or more at that time because of the breakdown of your relationship and you did not have a new spouse on December 31, 2023.