"What happens when the one you love is not the one you're with…"
Kurt glances at his boyfriend, who seemed to enjoy himself with practicing with Rachel. He sighs, he was not jealous or anything, it was just expected. Their duets don't nearly sound as good, so he says he totally understands. He reassures Blaine time and time again that it was okay. What's left to be jealous about when he's got little to no romantic feelings for the guy smiling across the choir room as if dedicating the song to him. He gives him a small smile and sighs when his boyfriend looks away. What happened along the way, he didn't know. Whenever they spend dates together, it seems like going out with a friend. No butterflies in the stomach, no giddiness and more importantly no spark with just the merest brush of skin. If only he feels this way towards Blaine, he would be happy. But he doesn't feel this way towards Blaine, he never did, it was just a crush. And after him being kissed by Blaine, it all seemed too good to be true that he accepted them. All the while he keeps thinking to himself that it will take time, that he's new to all this, that he was just in shock and the feeling's yet to sink in, all the different reasons he could think of, just to justify this relationship. But it was, unfortunately a dead end.
His heart beats for another guy he knows he couldn't have. It must be his disease. Kurt always wants what he can't have. Overtime, it just became a routine for him to detach himself from love, it seems that fate, or destiny or whatever, doesn't want him to be happy when it comes to romance. He sighs again. He just hopes that this bottled up feelings would just go away. But what can he do when the guy he has feelings for was always with him. How can he turn away from his best friend? Yes, that's the highest possible relationship they can have. That's why this has been a problem. This whole thing is just wrong. Firstly because he is with Blaine. Secondly, Sam is straight. Lastly, they are best buddies, and he doesn't want to ruin that.
Clearly his mind and his heart are not in sync. His mind knows that they could only be friends. But his heart already reached conclusions. It was sad really, constantly being at war with it. A battle with the heart is not easily won. When did everything become so complicated? Every time, Sam and him hang out together, he needs to rein in all the emotions. The way butterflies erupt in his stomach with a smile from Sam. The way his heart pounds with the sound of Sam's laughter. The way his cheeks flush with Sam's touch. He can't possibly let Sam know this. So he pretends and takes control. He locks up all this feelings because it isn't right it's wrong.
When the bell rang, Blaine and Kurt exited together, hands entwined. A sad smile graces Kurt's face and meets Blaine's radiant one. And from then one, he could feel how everything just went wrong, and the further this goes the more wrong it will become. He doesn't think about it because he can't do anything so he just goes on.