For a person who's alive:

 -a living spouse/ex-spouse is always referred to as "wife/husband" or "ex-wife/husband"
 -a deceased ex-spouse is always referred to as "ex-wife/husband"
 -a deceased spouse's designation depends on the total number of partners:
    -"late wife/husband" if there are no other partners of any kind
    -"<ordinal> wife/husband" if there are other partners

2. For a person who's deceased:

 -an ex-spouse, living or deceased, is always referred to as "ex-wife/husband"
 -spouses, living or deceased, depend on the total number of partners:
    -"wife/husband" if there are no other partners of any kind
    -"<ordinal> wife/husband" if there are other partners

"widow" and "widower" are only used in the immediate family text.