<P> In the first episode of the third season, "The Purple Piano Project", Blaine transfers to McKinley High at the beginning of his junior year to be closer to Kurt, who is a senior, and joins New Directions . He later auditions for the role of Bernardo in the school musical West Side Story, so as not to compete against Kurt who wants to play the male lead, Tony, but is cast as Tony himself . In the episode "The First Time", Blaine is pursued by Sebastian Smythe (Grant Gustin), a new Dalton Academy Warbler . Kurt and Blaine meet up with Sebastian at a gay bar, Blaine gets drunk, and afterward tries to get Kurt to have sex with him in the car . Kurt refuses, they have a fight, and Blaine decides to walk home . After the West Side Story opening night, they apologize to each other, and decide to go to Blaine's house . They are later shown in bed together, apparently having just had sex for the first time . When New Directions and the Warblers informally compete in "Michael" to determine which club can perform Michael Jackson's music at the upcoming show choir Regionals, Sebastian throws a slushie containing rock salt at Kurt, but Blaine interposes himself and is hit in the eye; his cornea is badly scratched and requires surgery . His eye heals, and he is back in time for New Directions to defeat the Warblers at Regionals . Blaine's older brother Cooper (Matt Bomer), a successful actor in commercials, visits Ohio, and the two achieve a rapprochement . Blaine's relationship with Kurt is later strained when Kurt text - flirts with a boy he met while preparing for his NYADA audition, and by Kurt's eagerness to leave for New York after graduation, which would separate the two at least until Blaine graduated the following year . The two patch things up, the glee club wins at Nationals, and the pair is still a couple at the end of the school year, though Blaine is still uneasy about the prolonged physical separation facing them . </P> <P> In the first episode of the fourth season, "The New Rachel", Blaine becomes the lead singer of New Directions and successfully prompts Kurt to follow his New York City dreams . In addition, Blaine successfully runs for senior class president with Sam (Chord Overstreet), and the two subsequently develop a friendship . Kurt inadvertently pulls away from Blaine due to his Vogue.com internship; distraught and feeling isolated from his friends, Blaine cheats on Kurt . After confessing to Kurt of his infidelity, Kurt severs all ties . New Directions' Nationals trophy is stolen by Hunter Clarington (Nolan Gerard Funk), the new captain of the Dalton Academy Warblers . When Blaine goes to Dalton Academy to retrieve it, Hunter and Sebastian attempt to seduce Blaine into returning to the Warblers . Blaine becomes conflicted, believing that he does not belong in New Directions . Sam ultimately convinces him that, despite having done a bad thing to Kurt, Blaine is still a good person and an important member of New Directions . </P> <P> Kurt begins to mend their relationship in "Thanksgiving", just before New Directions loses at Sectionals to the Warblers, and they spend Christmas together in New York City . Though he and Kurt continue to be on good terms, Blaine finds himself developing a crush on his best friend, Sam, which he knows will come to nothing as he knows Sam is not gay; the two of them team up to find evidence that the Warblers cheated at Sectionals, which means New Directions will be competing at Regionals . He ends up going to the Sadie Hawkins dance with Tina Cohen - Chang (Jenna Ushkowitz), who has developed a crush on him, but as friends only . When Kurt comes to Lima for the wedding of glee club director Will (Matthew Morrison) and Emma (Jayma Mays)--which Emma flees--he and Blaine make out beforehand, and sleep together afterward, though they do not resume a permanent relationship . </P> <P> Blaine had briefly joined the Cheerios when it looked like New Directions would be disbanding after their Sectionals loss, and cheerleading coach Sue (Jane Lynch) blackmails Blaine into rejoining; Blaine and Sam hatch up a plan to bring Sue down from the inside . Blaine eventually confesses to Sam that he has feelings for him, to which Sam assures him that he is somewhat flattered by Blaine's honesty and attraction, and that it would not change the fact that Blaine is still Sam's best friend . Blaine still loves Kurt and asks Burt for his permission to propose to Kurt, but Burt tells him they're too young to marry, and advises him to wait . Blaine remains determined, however, and while shopping for a ring, he meets Jan (Patty Duke), a lesbian jeweler who has been with her partner Liz (Meredith Baxter) for over thirty years . Jan offers to be a mentor to him, and Blaine and Kurt later have dinner with Jan and Liz, where Jan and Liz explain how their relationship evolved over the years and their experience with the growing mainstream acceptance of gay people . New Directions wins at Regionals, and Will and Emma get married immediately afterward, with the glee club, plus some graduates including Kurt, in attendance . Blaine is shown, after the ceremony is over, holding a jewelry box behind his back . </P>

When do kurt and blaine get back together in season 4