It started off as a publicity stunt, if Kurt was being honest.
Blaine had been flirty from the get go and Kurt liked him well enough. He was cute and friendly and really seemed to like Kurt.
And Kurt really wanted to win this thing.
He figured he wasn't hurting anyone by using Blaine's overly flirty nature to his advantage (after all, Blaine couldn't legitimately have feelings for someone he met while filming a reality TV show).
So they started 'dating'. The audience loved it and soon Kurt and Blaine were down to the last five contestants left. Kurt had begun hoping that he and Blaine would still be friends when this was all over. The guy was really starting to grow on him.
It was a normal (almost boring, considering this was reality TV) day when everything changed. Kurt and Blaine were snuggling together on the couch - not an unfamiliar position for them - flicking through the limited channels they had on the TV. Kurt hadn't even noticed Blaine had been staring at him until he realized they had been watching a golfing competition for a full five minutes. He had barely turned his head when Blaine blurted it out.
"I want to marry you."
Looking back, Kurt couldn't exactly pinpoint when his and Blaine's relationship had changed from fake to real. All he knew was that it had, and that he was in love with Blaine.
"What?!" Kurt choked out. He might be in love with the guy but a marriage proposal on reality TV was not something he took lightly.
Blaine, at least, had the decency to blush, apparently realizing what he had said wasn't very tactful. "Not right now, obviously. And this isn't an official proposal - I don't even have a ring or anything. I'm just letting you know that I want to marry you. Someday."
Kurt gave him a watery smile and for the first time since the cameras started rolling he felt as though he and Blaine were the only two people in the whole world.
"I want to marry you too. Someday."
At the end of it all, it was Blaine who won - the pseudo-marriage proposal really captured the hearts of the viewers - but it didn't matter. Kurt had won something much more valuable.