Blaine flirts with Kurt, and in Wonder-ful Blaine asks permission from Burt to ask Kurt to marry him.Burt, while happy that Blaine is so in love with his son, explains to Blaine that they are too young, and that they are meant to be together so he should just relax and everything will be OK.Their relationship is taken to the next step in Season Three when Blaine transfers to Mc Kinley and the New Directions, because he can't stand to be apart from the person he loves.Kurt and Blaine share loving looks during some songs and rarely fight, only having three fights during the course of their relationship so far (The First Time, Dance with Somebody and The Break-Up).Their relationship is once again tested by their new lifestyle and Kurt's newfound confidence that puts them in an uncomfortable position, and Blaine finally decides to move out to draw lines between them and learn how to live in the big city.After awhile, when Rachel moves to LA, Blaine moves back in with Kurt and they live together in the loft.In The Break-Up, Blaine surprises Kurt by showing up in New York early.
They maintain their long distance relationship successfully at first via skyping and texting, but with conflicting schedules, things start to slide quickly.
This is the episode in which they share their first kiss, and it is assumed that they start dating very soon afterwards.
In the episode New York Blaine tells Kurt that he loves him for the first time, to which Kurt replies that he loves him too.
Kurt and Blaine make up in Thanksgiving, and then as a Christmas present, Burt brings Blaine to New York in Glee, Actually, and, while ice skating, Kurt and Blaine duet White Christmas.
At the end of the season, Kurt arrives in Lima to support his dad at his appointment, having recently found out that Burt has stage 1 cancer, and visits Mc Kinley with Mercedes and Mike to see the New Directions.