It seems to me that a man who, upon sensing that someone is making an assumption that his (male) flatmate is his boyfriend, would utter the phrase “I’m not gay!” is unlikely to comfortably and happily identify as bisexual.
Ivy says what I mean better than I do.
I don’t know how much John understands what he’s doing, either. He seems to have at least some conscious idea, but then again I’m pretty sure it’s not a complete conscious idea. And I’m awfully curious how much he lies to himself or disregards what he’s really feeling because he doesn’t want to believe it’s what he’s feeling. Because as of s3, clearly that’s also a Thing He Does.
And I put that in caps, because it’s a thing he does of enough notoriety that the people around him recognize it as a Thing He Does.
Which I think is one of the things that has our heads spinning about this season. ”I’m not gay!” he shouts, and some of us giggle because ‘protest too much,’ and some of us growl because queerbaiting, but dammit, you respect a person’s call about their own identity. But now, if he can delude himself that thoroughly about the woman he married and why he married her—and on the same point as the reason he’s attracted to these men—then we are being invited to doubt John’s reliability when it comes to his own identity re: his relationships.
So now what?
And I think Sherlock knows too, on some level—quite possibly a more conscious level than John most of the time, because Sherlock doesn’t much like feeling things but he does like to understand what’s going on (and he’s clearly made an effort this season to understand what’s going on with himself when it comes to John).