Question: Who was Taylor Swift addressing in the song "Should've Said No"?

Context articles: Our Song (Taylor Swift song)
Picture to Burn
Teardrops on My Guitar
Taylor Swift discography
The Taylor Swift Holiday Collection
Taylor Swift (album)
Should've Said No
Beautiful Eyes
White Horse (Taylor Swift song)
Fearless (Taylor Swift song)

"Our Song" is a country song performed by American singer-songwriter Taylor Swift.
 The song was written by Swift and produced by Nathan Chapman.
 It was released on September 9, 2007 by Big Machine Records as the third single from Swift's eponymous debut album, "Taylor Swift" (2006).
 Swift solely composed "Our Song" for the talent show of her freshman year in high school, about a boyfriend who she did not have a song with.
 It was included on "Taylor Swift" as she recalled its popularity with her classmates.
 The uptempo track is musically driven mainly by banjo and lyrically describes a young couple who use the events in their lives in place of a regular song.
"Picture to Burn" is a song recorded by American singer-songwriter Taylor Swift.
 It was co-written by Swift and Liz Rose, and produced by Nathan Chapman.
 It was released on February 3, 2008 by Big Machine Records as the fourth single from Swift's eponymous studio album, "Taylor Swift" (2006).
 It was inspired by the narcissistic and cocky nature of her former high school classmate and ex-boyfriend Jordan Alford with whom Swift never established a formal relationship.
 In retrospect, Swift has stated that she has evolved on a personal level and as a songwriter, claiming she processed emotions differently since "Picture to Burn".
 The song was chosen as a single based on the audience's reaction to it in concert.
 Musically, the track is of the country rock genre with prominent usage of guitar, banjo, and drums.
 The lyrics concern setting fire to photographs of a former boyfriend.
"Teardrops on My Guitar" is a song by American singer-songwriter Taylor Swift.
 The song was co-written by Swift, alongside Liz Rose and produced by Nathan Chapman with Swift's aid.
 "Teardrops on My Guitar" was released on February 19, 2007 by Big Machine Records, as the second single from Swift's eponymous debut album (2006).
 The song was later included on the international release of Swift's second studio album, "Fearless" (2008), and released as the second pop single from the album in the United Kingdom.
 It was inspired by Swift's experience with Drew Hardwick, a classmate of hers for whom she had feelings.
 He was completely unaware and continually spoke about his girlfriend to Swift, something she pretended to be endeared by.
 Years afterwards, Hardwick appeared at Swift's house, but Swift rejected him.
 Musically, the track is soft and is primarily guided by a gentle acoustic guitar.
 Critics have queried the song's classification as country music, with those in agreement (such as Grady Smith of "Rolling Stone") citing the themes and narrative style as country-influenced and those opposed (such as Roger Holland of "PopMatters") indicating the pop music production and instrumentation lack traditional country elements.
American singer-songwriter Taylor Swift's career began with a record deal with Big Machine Records in 2005 and the release of her eponymous debut album the following year.
 In the United States, "Taylor Swift" peaked at number five on the "Billboard" 200 and stayed the longest on the chart during the 2000s.
 All of its singles—"Tim McGraw", "Teardrops on My Guitar", "Our Song", "Picture to Burn", and "Should've Said No"—charted within the top forty in the United States and were certified platinum by the RIAA.
 Swift followed with the release of the EPs "" and "Beautiful Eyes", which peaked at number twenty and number nine on the "Billboard" 200, respectively.
The Taylor Swift Holiday Collection, originally titled Sounds of the Season: The Taylor Swift Holiday Collection, is a Christmas EP by American singer Taylor Swift.
 The EP was first released on October 14, 2007 by Big Machine Records exclusively to Target stores in the United States and online.
 The release was originally a limited release for the 2007 holiday season, but was re-released to iTunes and Amazon.com on December 2, 2008 and again in October 2009 to Target stores.
 "The Taylor Swift Holiday Collection" features cover versions of Christmas songs and two original tracks written by Swift, "Christmases When You Were Mine" and "Christmas Must Be Something More", all of which have a country pop sound.
Taylor Swift is the debut studio album by American singer-songwriter Taylor Swift, released on October 24, 2006, by Big Machine Records.
 Swift was 16 years old at the time of the album's release and wrote its songs during her freshman year of high school.
 Swift has writing credits on all of the album's songs, including those co-written with Liz Rose.
 Swift experimented with several producers, ultimately choosing Nathan Chapman, who had produced her demo album.
 Musically, the album is country music styled, and lyrically it speaks of romantic relationships, a couple of which Swift wrote from observing relationships before being in one.
 Lyrics also touch on Swift's personal struggles in high school.
"Should've Said No" is a song written and recorded by American singer-songwriter Taylor Swift.
 The song serves as the fifth and final single from her self-titled debut studio album.
 The song is about Swift addressing her former lover who cheated on her.
 It became her second number-one single on the "Billboard" Hot Country Songs chart, and was a Top 40 hit on the "Billboard" Hot 100.
 In addition, "Should've Said No" has been certified platinum by the Recording Industry Association of America (RIAA).
Beautiful Eyes is the second extended play (EP) by American singer-songwriter Taylor Swift.
 The EP was released on July 15, 2008 by Big Machine Records exclusively to Walmart stores in the United States and online.
 The limited release EP has a primarily country pop sound and features alternate versions of tracks from her debut album, "Taylor Swift" (2006), and two original tracks, "Beautiful Eyes" and "I Heart ?"
, songs which she had previously written; a DVD, featuring music videos of singles from "Taylor Swift", is also included on the physical release of the EP.
"White Horse" is a song performed by American singer-songwriter Taylor Swift.
 The song was written by Swift and Liz Rose and produced by Nathan Chapman, with Swift's aid.
 The song was released on December 7, 2008 by Big Machine Records, as the second single from Swift's second studio album "Fearless" (2008).
 Swift and Rose composed the song about one of Swift's ex-boyfriends, when Swift discovered he was not what she had perceived of him.
 It focused on the moment where Swift accepted that the relationship was over.
 "White Horse" is, musically, a country song and uses sparse production to emphasize vocals.
 Lyrically, the track speaks of disillusionment and pain in a relationship, drawing references to fairytales.
"Fearless" is a country pop song performed by American singer-songwriter Taylor Swift.
 The song was co-written by Swift in collaboration with Liz Rose and Hillary Lindsey and produced by Nathan Chapman and Swift.
 "Fearless" was released on January 3, 2010 by Big Machine Records as the fifth and final single from Swift's second studio album of the same name (2008).
 Swift composed the song while traveling on tour to promote her eponymous debut album, "Taylor Swift" (2006).
 She wrote "Fearless" in regard to the fearlessness of falling in love and eventually titled her second studio album after the song.
 Musically, it contains qualities commonly found in country pop music and, lyrically, is about a perfect first date.