Maybe you should straight up ask, You passive aggressive trashcan.
He must not really want to know.
Maybe he likes the constant question mark there. As long as he never gets an answer to that question, he can keep this precariously intimate relationship under control, and keep it status quo without having to overturn too many self-perceptions.
If he asks, he has to live with the definite knowledge that Sherlock is gay, and the pressure is sort of on, right? Proceed or get of the pot, so to speak. Lots of difficult questions to cope with in that case, right?
If he asks and has to know for certain that Sherlock is straight, then he also would have to accept that there’s no actual sexual tension between them and it’s all in his head. And we’ve already seen how he reacts to that revelation. (With intense, burning, murderous anger and jealousy.)
If he asks and Sherlock says he’s bisexual, I don’t know what John would do, frankly.
But as long as John doesn’t ask, and as long as he doesn’t actually know for sure, well…sexual tension blooms, intimacy runs high, and John has perfect plausible deniability for neither acting on it nor restraining it.
I love that John’s bravery is his dominant trait, but that he’s a complete coward when it comes to this.