Based off of spoilers for 4.06. I gave myself (and a bunch of people on tumblr) a sad, so be prepared.
Kurt was standing on the now empty stage next to Rachel as they talked to Finn about the play. Rachel was too nervous to talk to him herself, which is why she had dragged Kurt along. A flicker of movement behind his brother caught his eye and he looked over to see Blaine walking towards them, still in his teen angel costume. He stopped next to Finn, his eyes never leaving Kurt, who turned to look at Rachel.
"I'm going to wait in the car," he said. "Congratulations, Finn, Blaine, the play was great." Without so much as a glance more in Blaine's direction, Kurt hurried out, taking deep breaths through his nose.
The door behind him crashed open and he picked up his pace. He couldn't handle talking to Blaine right now, he just couldn't.
Please let it be Rachel, please let it be Rachel…
"Kurt, wait!"
Shit.
A warm, familiar hand caught his elbow and Kurt whirled around, whipping it from Blaine's grasp. "Don't touch me, just-"
"Please, I just want to talk to you."
Kurt hated himself for looking into those big, sad eyes, taking in the redness, the dark circles under his eyes, barely concealed by the stage make up Blaine hadn't washed off. "What, Blaine? What could you possibly say to me that you haven't already said a thousand times over? I get it, you say you're sorry, you beg for my forgiveness."
"Kurt, I-"
"No," Kurt waved him off, "it's my turn to talk. You keep saying all this stuff, over and over, and it doesn't make it better, Blaine; it doesn't help. If anything, it makes it hurt worse because I'm trying to get over this, I'm trying to mend my broken heart but, damn it, you won't give me any space! You're constantly texting me or IM'ing me or, or, or sending me gifts! I don't want them, Blaine." Kurt paused, taking a deep breath and crossing his arms protectively over his chest. "I want you to stop, Blaine. I need time to think about everything, to figure out if I ever want to see you again. I need time and I need space and right now, you're not giving me either. No more calls. No more texts. No more flowers or boxsets or fruit baskets or anything, okay? Just give me the one thing I'm asking for right now."
Kurt tried like hell to ignore the tears streaming down his cheeks but the ones tracking slowly down Blaine's. "I love you, please don't-"
He shook his head, slowly backing away. "No, Blaine, no, you don't get to say that anymore. We're done; this is me breaking up with you, officially. Goodb-"
"NO," Blaine shouted, shaking his head furiously. "No, please don't say goodbye, you swore you never would. I'll stop, I'll stop everything, just please, don't say it."
Kurt stared at him for a long moment. "I guess we're both breaking promises, then, aren't we? Goodbye, Blaine."
He refused to acknowledge the sound of Blaine crumbling to the floor, his sobs echoing down the deserted hallway as Kurt ran outside, his throat aching from holding in all of the noises that were desperate to escape.