I know that women have been elected as Presidents of many countries in the world, although that has yet to happen in the United States. But has there ever been an instance of a country where a President was elected, and then his or her spouse was elected at a later day to be President? I haven't heard it mentioned one way or another, and am quite curious.
Yes. Argentina had one of those, and a closely related situation.
Also in Argentina, Juan Perón died while in office and was succeeded by his wife Isabel Martínez de Perón, but that does not qualify because she was not directly elected as President (she succeeded Juan Perón because she was the Vice President).
Well, Sonia Gandhi, the Italian-born widow of the assasinated Rajiv Gandhi won the 1998 election to the leadership of the Congress Party - the political party that has governed India for most of the time since independence from Britain in 1947.
She remained in that office for 22 years, and led the party to victory at the 2004 elections - but she declined the premiership in favour of Manmohan Singh.