Kurt met a girl in college, and eventually married her and they were expecting a baby together. The baby was born, but the mother, his wife died. His daughter had some kind of condition and he took her for treatment at Blaine's clinic or sort. The two hit it off, and I think Blaine used music to approach Kurt's daughter? Mercedes was also part of the story, and Kurt had some sort of meltdown when he realized he may be falling if love with Blaine. He still maintained touch with his late wife's parents. Klaine endgame.