Maybe it happens after Sherlock's return, or in a different verse. The thing is, John grows somewhat distant from Sherlock (if it's after Sherlock's return, it's probably quite logical). He spends less and less time together with Sherlock, he has his own hobbies, spends more time with his friends, dates, etc. And he's oblivious of the fact that it really hurts Sherlock. He's jealous, hurt, feels abandoned, unloved. He misses John's attention, John's praise; he misses everything they used to have. They still have cases together, but it's not the same (maybe it's partly imaginary though). Sherlock starts thinking that John has only needed him to provide dangerous situations now and then.
Sadly, the more distant John becomes and the more nights he spends away from home, the more Sherlock realises that he's in love with him. His feelings make him panic, feel empty, and so on, because it's just not like him and he can't deal with it. There's absolutely no evidence that John feels anything even remotely like what Sherlock feels. On the contrary, John has his own life and Sherlock no longer has as much place in it as he did before.
To his own disgust he becomes so desperate that he starts taking absolutely unnecessary risks and getting hurt on purpose, just to have John there with him. And John is there to save him, as a soldier and as a doctor, who at least cares 'somewhat'. And it gives Sherlock his attention and care. After some time it becomes clear to John that it's not a coincidence that Sherlock has been in so much trouble lately, sometimes getting very seriously injured. It's gone too far. Other people also start seeing that something is definitely wrong even by Sherlock's standards.
John confronts him, maybe shouts at him, maybe he also drags him to get tested for drugs, not knowing what else is there so terribly wrong to make Sherlock act like that. John is very worried and is probably a bit too harsh and angry at Sherlock because of being concerned for his life.
It only makes things worse for Sherlock. He's ashamed and disgusted with himself for his own attention-seeking behaviour and for the feelings that John doesn't return. Slowly, but surely, it breaks Sherlock.
I want a lot of heartbreak and angst.
The ending can be good: John learns what exactly is going on. Sherlock's feelings are not as unrequited as he thought. They get together and it has a healing effect on Sherlock, everything's better, even though the whole relationship thing is new to him. But John is there, so it's okay. (I prefer top!John if you want to include any sex scenes)
I also don't mind if the ending is bad, instead: John doesn't know what to do, doesn't know how to deal with Sherlock's self-destruction. It's too much. So, while it's heartbreaking to him, he leaves Sherlock to sink all alone.
John/Sherlock (unrequited???). Angst. Self-harm. Depression. Hurt!Sherlock.
Sadly, the more distant John becomes and the more nights he spends away from home, the more Sherlock realises that he's in love with him. His feelings make him panic, feel empty, and so on, because it's just not like him and he can't deal with it. There's absolutely no evidence that John feels anything even remotely like what Sherlock feels. On the contrary, John has his own life and Sherlock no longer has as much place in it as he did before.
To his own disgust he becomes so desperate that he starts taking absolutely unnecessary risks and getting hurt on purpose, just to have John there with him. And John is there to save him, as a soldier and as a doctor, who at least cares 'somewhat'. And it gives Sherlock his attention and care. After some time it becomes clear to John that it's not a coincidence that Sherlock has been in so much trouble lately, sometimes getting very seriously injured. It's gone too far. Other people also start seeing that something is definitely wrong even by Sherlock's standards.
John confronts him, maybe shouts at him, maybe he also drags him to get tested for drugs, not knowing what else is there so terribly wrong to make Sherlock act like that. John is very worried and is probably a bit too harsh and angry at Sherlock because of being concerned for his life.
It only makes things worse for Sherlock. He's ashamed and disgusted with himself for his own attention-seeking behaviour and for the feelings that John doesn't return. Slowly, but surely, it breaks Sherlock.
I want a lot of heartbreak and angst.
The ending can be good: John learns what exactly is going on. Sherlock's feelings are not as unrequited as he thought. They get together and it has a healing effect on Sherlock, everything's better, even though the whole relationship thing is new to him. But John is there, so it's okay. (I prefer top!John if you want to include any sex scenes)
I also don't mind if the ending is bad, instead: John doesn't know what to do, doesn't know how to deal with Sherlock's self-destruction. It's too much. So, while it's heartbreaking to him, he leaves Sherlock to sink all alone.
+ please, no Mary in this verse, if possible.