Work Text:
“JOHN: We´re not a couple
IRENE: Yes you are.”
Sherlock and John both use the pronoun “we” to refer to themselves when under emotional stress.
The two times this appears on the show, there is a woman threatening their relationship. The first time I noticed this is in ASiB; after John meets Irene and has the famous dialogue cited above, which is overheard by Sherlock, we have a very interesting scene:
John is jealous of Irene, and tries to know how Sherlock feels about her being alive. We have just seen Sherlock walking the street in a haze, very affected by the conversation he overheard, either because it´s a shock to him to know that Irene is alive, but most probably because he has realized he feels things for John (and the sentiment is maybe returned and they are indeed a couple). In this scene John feels left behind, and we see that Sherlock has “turned his back” on him.
The second time this happens in HLV, John has just heard about Mary´s lies. Now is John who is “turning his back” on Sherlock (at least visually):
After an extremely emotional scene, Mary has been demoted from friend and wife to a mere client and Sherlock and John will decide together, as a couple, if she has a place in their lives. Despite denial, John and Sherlock are indeed a couple and face emotional situations as a unit, "we". But apparently John is the only one who can verbalize it and Sherlock doesn´t correct him.