A S4 AU where post Blaine cheating, Kurt meets Sebastian [they're the same age] in New York. Their initial meetings are full of tension and a bit of awkwardness because they never interacted with Blaine not in the picture. Sebastian having grown as a person is scandalized that Blaine cheated, he jokes that he's upset that it wasn't with him.
But they keep meeting, neither can tell why they keep coming back to the same bar or cafe, but they keep coming back. They talk, Kurt talks about Vogue and NYADA, Sebastian talks about NYU or Columbia [insert major]. After a few meetings, Sebastian has a moment of 'damn he's hot now' and Kurt has a moment of 'he's really pretty when he's being nice'.
They both freak out about it, Kurt because it's Sebastian and Sebastian because he kind of wants like more than a one night stand with Kurt/wants to hold his hand/aahhhhh?? Kurt tries to date other people, like Adam, and Sebastian gets really jealous.
Kurt goes back to Lima for Will's wedding, and Blaine tries to hook up with him. Kurt almost accepts but can't knowing he has growing feelings for Sebastian. The moment solidifies it for Kurt that these feelings aren't going away.
When he gets back to NY, Kurt starts focusing on Sebastian, trying to figure out if his feelings are unrequited or not. Eventually Sebastian bites the bullet and kisses Kurt on one of their outings, Kurt freezes before smiling and kissing back.
Back in Lima, Blaine is devastated from losing Kurt, even more so when Kurt starts posting pictures with Sebastian, he is absolutely gutted when Kurt's status changes from 'Single' to 'In A Relationship with Sebastian Smythe'.
Most of the New Directions are not cool about it, talking shit about Sebastian and asking Kurt how he could do this to Blaine. [Weird how none of them are getting onto Blaine about it] The only few on his side are his roommates [Rachel and Santana] and his stepbrother.
Blaine graduates and goes to NYADA, but very quickly falls apart with Kurt and Sebastian's relationship now on full display in front of his face. He drops out and moves back to Ohio, transferring to a state school while he figures out his next steps.
He goes to Scandals one night and meets Dave, Blaine tries to jump into a relationship but Dave can tell he's not ready for one. He's like, "I like you dude, but you need to figure yourself out first."
So Blaine does, he blocks Kurt for a bit so that he isn't constantly seeing what he's up to. He gets a therapist, he continues his education and finds himself wanting to be back with the Warblers, he loved show choir, he felt best doing show choir and being at Dalton. So he adjusts his major and makes that his new goal.
When he's eventually in a better place, him and Dave revisit the possibility of a relationship.
And both Kurt and Blaine get to be happy, it's not with the person they thought it would be, but they're happy and that's what matters.
