I will honestly eat my hat if there is not a scene similar to this at some point during season 3.
As Blaine walked in he saw the two boys laughing congenially. Their easy and transparent camaraderie both bemused and amused him. Not so terribly long ago they had been enemies of a sort, hostile adversaries playing out a very strange game of cat-and-mouse, where Kurt knew a secret about Dave that had caused the closeted jock to come after his boyfriend in often violent and always perverse ways. However, Dave had eventually come around to acknowledging his sexuality, if only privately, and had subsequently worked very hard to make amends to the boy who used to be the external target of his self-hating harassment.
So far so good. But as time had gone by Kurt's long-held desire to help Dave had caused the two boys to develop a real intimacy and friendship with one another. And while Blaine believed it was only friendship on Kurt's part, he had the distinct suspicion that Dave's feelings towards his boyfriend had some time ago exceeded the bounds of just friendship. After all, this whole drama had kicked off between the two of them precisely because Dave had kissed Kurt.
Blaine had never been entirely sure whether Dave's actions were the product of a genuine desire for Kurt, specifically, or if he had, in Dave's mind, been merely a stand-in for 'gay-man.' At first Blaine had been more inclined to think it was the latter, and perhaps it had been the latter, at first. But whether or not such had been the circumstance in the past, it was not hard to see that nowadays Dave feelings toward his former tormentee were anything but platonic.
It was not that Blaine begrudged the friendship Kurt and Karofsky had managed to forge in spite of their past antagonism. In fact at first he had actively encouraged it. Blaine knew is salved something in his boyfriend to be able to help someone else who was in distress over their sexuality. Kurt was an intensely loving and forgiving person who wanted to make the world better, and those were some of the qualities that Blaine loved best in him. And as for Dave, like Kurt, Blaine also felt an underlying impulse to help those struggling to accept themselves. Dave need that help and he deserved it, in Blaine's estimation, especially in light of all that he had done to make amends to the one he had most hurt while still in denial.
But, it was becoming clearer every day that, whatever Dave's true feelings were for Kurt in the past, in the present, he was becoming exponentially more and more infatuated with Kurt. And it was not at all difficult to understand why. Not only did Kurt know Karofsky's secret, and not only was he gay himself, Kurt was also just a wonderful person to be around. He was funny and sweet and just a little bit outrageous, always so sure of his convictions and yet so endearingly unsure of himself. Not to mention he was way sexy. And smart, and talented, and… In light of Kurt's immense desirability, it would have been exceedingly strange for Dave not to develop feelings for the other boy.
The real problem here was not, in fact, Karofsky's emotional and sexual disposition toward Blaine's boyfriend. The real problem was said boyfriend's apparent obliviousness to it all. After Kurt had taken Dave under his wing, the two boys had become fast friends, spending a great deal of time together and forging a genuine intimacy with one another. And while Kurt probably had no notion that he was leading Dave on, Blaine could see as plain as day, that that was nonetheless the reality of the situation. Kurt did not know his own desirability and so he still perceived Dave's attentions and affections as being of a thoroughly platonic ilk. But sweet as that delusion was it was still just that: a delusion.
Most of the time Blaine found Kurt's underestimations of himself to be nothing but endearingly sweet; however in this particular instance, it was going to be a major barrier toward getting Kurt to see the reality of the situation. Kurt was genuinely deluded as to the level of his own attractiveness and because of that Blaine knew he was going to have a serious uphill fight in convincing his boyfriend that his concerns were not just the paranoid fantasies of a jealous lover. Kurt needed to understand what he was doing to Dave; Blaine could not in good conscious allow the two of them to continue forging this deepening friendship without laying bare the more lustful feelings that were clearly brewing underneath this ostensibly platonic camaraderie.
However he just knew Kurt was going to lash out at him for suggesting such a thing, so he had been putting it off. He didn't want to fight with Kurt. But he knew if he did not intervene soon, a repeat performance of the locker room was an inevitability.
Walking towards their table in the Lima Bean with a strong sense of purpose, Blaine made a beeline specifically for Kurt. Spotting him, Kurt's eyes brightened, and he had just enough time to say "Hey!" before Blaine leaned down and gave his boyfriend a possessive kiss.
Kurt was clearly taken aback by this, which Blaine had partially intended. Although they certainly did not hide when they were in public, they both tended to shy away from very overt displays of affection. In this instance, however, it was called for. Despite his legitimate concerns about Kurt unintentionally leading Dave on, Blaine also did just feel the need to remind Dave, in no uncertain terms, that Kurt was already spoken for. There was a part of him that felt a purely childish need to stake his claim.
Pulling out of the kiss slowly, Blaine lingered and said softly, "Hey." Kurt looked a bit dumbfounded, an expression so adorable Blaine had to exert a gargantuan level of self control not to pull him out of his seat on slam him up against the nearest wall. As a means of quelling this desire, Blaine shifted his expression to the other person present, sitting directly across the table from Kurt.
"Hi, Dave," Blaine said kindly, with no hint of sarcasm or resentment.
Dave expression was distinctly wide-eyed. Blaine could see etched in his face two strong and rather disparate reactions. On the one hand, the boy's anxiety about being even a tangential part of such an ostentatious public display was clearly evident. On the other hand, it was also easily apparent that Dave had been deeply affected by the blatant eroticism of what he had just witnessed. Blaine could see that his pupils were abnormally dilated and his breathing had deepened considerably, and he could not deny that he found the other boy's reaction deeply amusing and satisfying.
"Hi," Dave eventually replied, his tone respectful but wary.
Having regained his composure, Kurt interjected enthusiastically, "Blaine grab a seat. Dave and I were just discussing the possibility of writing, directing and producing a musical stage version of Harry Potter and putting it on YouTube."
However, before Blaine could do as his boyfriend asked, Karofsky quickly called a halt to it.
"No don't bother. I've got to get going anyways."
"Aw seriously?" Kurt asked, looking genuinely disappointed as Dave stood up to gather his stuff. "We haven't even finished casting yet!"
"Sorry Kurt. We can pick this up some other time. See ya," Dave concluded, lifting his hand in a farewell gesture.
Kurt put on his best pouty face but said no more, waving good-bye to Dave in the manner of a beauty pageant contestant. Dave gave Kurt a large smile at this, then made a merely respectful nod to Blaine before turning around and making his way quickly to the exit.
Blaine took up Dave's vacated seat and steeled himself for what was to come next.
"Hey, aren't you going to get something to drink?" Kurt asked as he lifted his own non-fat mocha to his lips.
"Kurt we need to talk about something."
"Oh, my god! Are you breaking up with me? Why, what did I do? Is there somebody else?"
"No, Kurt, calm down. I'm not breaking up with you. It's nothing like that," Blaine quickly and firmly assured him, his tone infused with amusement at Kurt's overreaction.
"God, you scared me," Kurt exclaimed in relief, his right hand clutching his chest dramatically. After taking a few more calming breaths he then asked, "So, what did you want to talk to me about?"
"Dave, actually," Blaine responded, trying to keep his tone both serious and neutral at the same time.
"What about him?" Kurt asked, looking completely oblivious.
"Okay, before I say this I need you to promise me you aren't going to overreact or get all hysterical."
"When do I ever do that?" Kurt retorted, a bit defensively.
Without saying a word, Blaine simply gave his boyfriend a long, meaningful look. Soon enough Kurt relaxed back into his seat and laughed slightly, his expression indicating he remembered his mellow dramatic freak-out of only moments before. And eventually he verbally conceded.
"Fine, I promise I'll try to remain calm and collected," Kurt vowed, raising his right hand as if he were a cub-scout, or a trial witness. "Now will you please tell me what this is all about before I die of curiosity?"
Blaine took a deep breath and deliberately paused for a few seconds so his words would achieve maximum effect.
"I think Dave has a crush on you."
With his expression still serious, Kurt's eyebrows knitted together, indicating his predictable disbelief. Then, a moment later, he seemed to decide Blaine was joking and let out a snort of laughter.
"Seriously, Blaine. What about Dave?" Kurt asked, clearly convinced his companion's assertion had been intended as humor.
Becoming slight frustrated, Blaine let out a huff of annoyance and said, with all the sincerity he could muster, "I am being serious! Kurt that boy is head-over-heels, ass-backwards in love with you!"
Speaking very slowly, as if to suggest Blaine might be mentally unstable, Kurt then asked "Um, have you started some kind of experimental medication I don't know about? Perhaps something with hallucinatory side-effects?"
"Kurt, will you please be serious? I'm trying to have a real conversation here."
Kurt paused briefly in response to Blaine's transparently earnest plea. Taking a few deep, visible breathes he looked Blaine squarely in the eye before replying.
"Blaine I don't know what to tell you other than I think you really are imagining this."
"Kurt, I promise you, I really am not."
"Okay well, what on earth makes you think he's 'in love' with me, as you put it?"
Feeling a small amount of relief that Kurt was now at least willing to entertain the idea, Blaine tried to mount a convincing case.
"Well first of all, by your own admission he spends every single second with you that he possibly can."
Rolling his eyes at this, as if it was absurd to have proffered it as evidence, Kurt responded, "That's just 'cause I'm the only person at McKinley, besides Santana, that knows he's gay. He likes spending time with me because I'm the only one he can really be himself with. I really don't think it's all that personal; I'm just a lot nicer than Santana is."
"Kurt haven't you noticed when the two of you are together he laughs at everything you say and hangs on your every word. He acts like an infatuated 14 year old girl whenever he's with you."
Kurt looked slight discomforted at this observation but quickly hedged, "I think he's just trying to be nice to me to make up for how mean he used to be."
Sensing that he was beginning to make a dent, Blaine continued. "Oh, and let's please not forget how all of this started in the first place: he kissed you!"
"Yeah, but you know it was probably just 'cause I'm obviously gay. Again, I don't think it was personal. I'm pretty sure I was just a stand in."
"Kurt, don't you see that no matter what I say, there will always be some other way for you to explain it. But that doesn't mean I'm wrong. And you're right that none of these things individually is all that meaningful, but when you look at them together, I'm sorry but my explanation makes the most sense."
"Sweetie," Kurt responded delicately, "are you sure this isn't just irrational jealousy talking?"
However Blaine had anticipated this argument and already had the perfect rejoinder prepared. "Even if I were jealous, that doesn't make anything I've said any less true," he responded a bit smugly.
At this retort, Kurt sat back in his seat and gave his boyfriend a wary once-over. He seemed to be considering Blaine and his argument very seriously, now. After a long moment of silence, Kurt spoke again, his hedging words slow, his tone hesitant.
"Okay, well, let's assume for a minute – just for argument's sake – that you are right. What is it you think I should do about it? I mean, why is it a problem?"
"It's a problem because you can't lead him on!" Blaine exclaimed, grateful he finally had the opportunity to say what was really on his mind.
"Okay, even if I accept your theory that he has a crush on me – and that's still a big 'if' – I still don't understand how anything I've done could be construed as anything but friendly."
"Kurt, you're gay and you clearly enjoy hanging out with him. That's enough."
"I don't think so."
"Um, have you completely forgotten that's exactly how it was with you and me at first?"
Kurt all of a sudden looked very uncomfortable and Blaine could see he had made another serious dent. Still sticking with his skepticism, however, the other boy came back with an uneasy, "That's different."
"In what way is it different?"
"Well for one thing I never used to bully and harass you."
"That's true but Kurt, you know as well as I do that that bullying could easily have been because he liked you and he was angry at you for making him feel that way."
"Okay, fine. I concede that might be true. But still, all of this is circumstantial at best."
"Kurt if you are looking for completely bullet-proof evidence I don't have it. But seriously, you should see the way he looks at you sometime. That boy thinks the moon rises on your shoulders, the stars glint out of your eyes and the sun shines out of your ass."
Blaine could see very clearly the effect that his poetic yet blunt words had had on Kurt. The boy looked sheepishly flattered and Blaine could tell he was more than a little intrigued by the idea, if still a bit resistant to it. In fact, Blaine eventually had to call Kurt out of his reverie because the boy was starting to look wistful and it disturbed Blaine immensely.
"Kurt!"
"Sorry, I was just thinking. So," he continued after a brief pause, "let's say this theory of yours is true, more or less. What is it you think I should do about it?"
"I think you need to talk to him. You need to let him know, in no uncertain terms, that you and he are just friends."
"Even if you are right, odds are he'll be way too embarrassed to admit it. And if you're wrong, then I just look like a narcissistic idiot. There is absolutely no way of bringing this up without making things epically uncomfortable between us, and I don't want to do that. Especially since it's just as likely as not that you are imagining this whole thing."
Kurt gave a good long pause and then resumed with utter conviction. "I'm not going to mess up my friendship with him just because of how you think he looks at me," he declared firmly.
Blaine could see Kurt was adamant about this and there would be no more arguing with him at present. But he could also see that his words had gotten through. Knowing Kurt as he did, Blaine was sure the other boy would be mulling this over quite seriously for the rest of the afternoon and evening, even if it appeared that he had made up his mind, or had forgotten all about it. And Blaine could be satisfied with that for the minute.
"Okay fine. But I'm just saying this right now: when he tries to kiss you again, I'm going to give you the biggest I-told-you-so ever."
"I really think you are imagining this," Kurt retorted, his tone a bit hushed and pleading.
"That's only because you don't see yourself clearly at all. If you did, the only thing you'd be wondering is how he's managed to hold it back for this long."