Final answer:
Jimmy Carter and his wife Rosalynn Carter met in the fifth grade and were high school sweethearts, yet they did not marry until their mid-thirties.
Step-by-step explanation:
The president and his wife who met in the fifth grade, were high school sweethearts, and did not marry until their mid-thirties are Jimmy Carter and Rosalynn Carter. Jimmy Carter is well-known for his post-presidency humanitarian work and his time as the 39th President of the United States from 1977 to 1981. He and his wife, Rosalynn, have had a long-lasting partnership that began long before they entered the White House. Their early acquaintance and enduring relationship are notable facts about his life before and during his political career.