old flame (Noun)
A previous girlfriend or boyfriend; a former romantic partner, especially one for whom one still has romantic feelings.
"Old Flame" is a song written by Donny Lowery and Mac McAnally, and recorded by American country music band Alabama. It was released in January 1981 as the first single from the album Feels So Right. The song eventually became the group's third number-one single on the Billboard Hot Country Singles chart. According to Allmusic reviewer Al Campbell - it represented a traditional side to Alabama's repertore.