After Cas became human, it took a week for him to find the Winchesters, hitchhiking across the country and trying to figure out how to deal with this strange humanity. He learnt from experience when he needed to use the toilet, or take a shower, and what was and wasn't appropriate when you were using public transport. He learnt that dirty looking middle-aged men falling asleep on park benches were scorned and avoided, but that some people were still unfailingly kind and would give you food or money if you asked for it. In short, he learnt how to live.
Once he finally turned up at the bunker, he was met by an incredibly worried Dean who berated him for not calling or turning up sooner. Cas was tired, a feeling that he was still getting used to, and incredibly hungry, but he tried his best to explain his situation to Dean. Dean acted understanding and kind, feeding him home-cooked burgers and lending him clothes to sleep in after Cas had showered. Cas crawled into bed happy that his fall hadn't affected their profound bond – in his eyes, it hadn't changed anything.
For the next few days, everything was quiet, everyone needing to recuperate after the vents of the past few months. Sam was still very ill and weak, only crawling out of bed for a few hours a day and constantly coughing up blood. Sometimes, Cas would catch Dean giving him a wistful look, as if to say 'if you still had your powers you could cure him!' But nothing was ever said, and for that Cas was grateful – the loss of his grace was painful enough without being rubbed in.
Kevin popped in a couple of times, but he didn't like spending large amounts of time holed up inside the bunker – he had had enough of being forced to translate symbol after symbol from the various tablets, and was taking a well-earned break to get rid of the persistent migraine that so much studying had given him. Cas never really talked to Kevin, and generally stayed out of his way – not because he disliked him, but because he had nothing to say. He had messed up, he knew that, and while Dean and Sam were perfectly used to that, Kevin might not be so forgiving.
A week after Cas had arrived, Dean kissed him. It was entirely unexpected – Cas had been making toast in the kitchen, dressed in the baggy tracksuit pants he had been sleeping in, with Dean leaning against the counter taking a drink, when suddenly Dean had lurched across and captured Cas's lips. It had been short, but brutal, and Cas wasn't sure if he'd liked it – but he smiled anyway, understanding that it was a sign of affection, and didn't mention it again. He decided that if he didn't talk about it, the issue would probably go away – Dean had probably just been testing what Cas would do.
However, only a couple of days later Dean kissed Cas again. This time, they had both been sat on the sofa with Sam watching some programme that Cas barely understood. Sam had complained of tiredness and left to go back to bed, and almost as soon as the door was closed Dean had pounced, straddling Cas's hips and kissing him with such force Cas could only sit there and take it. He had hesitantly kissed back, unsure of what to do, and Dean had grabbed his face and made him kiss harder, until he could hardly breathe. They had remained like this for what seemed like hours, before Dean eventually pulled back and looked at Cas with an expression that showed such a blatant need for affection that Cas had felt obligated to smile tenderly up at him and reach up to run his hand across Dean's face in a gesture of love. Dean had smiled a brilliant smile and left, leaving Cas to wonder exactly what he had gotten himself into.
He loved Dean – he really did – but this was all so new, so foreign, and try as he might be just couldn't make it feel good like it was supposed to. But saying that to Dean didn't seem like a good idea so Cas just kept quiet, keeping his feelings to himself and putting on a mask every time anyone else was in the same room.
The strange dance continued for weeks – whenever they were alone, Dean would attack Cas with kisses and Cas would just take it, playing his part like a marionette. He felt nothing, nothing except emptiness, and he wandered through each day like a shadow, not really alive at all. Dean never noticed, entirely taken in by the act he was putting on, and Sam was far too ill to pay attention to anyone else. Even Kevin just smiled when he saw Cas, saying that he was happy him and Dean had finally realised their feelings and gotten together. Cas had thanked him without meaning it and moved on, brushing the incident aside like everything else that happened in this human life.
Of course, eventually it moved to the next level. Dean wasn't the sort of person to be satisfied with just kissing in a relationship for long, and one evening Cas found himself pinned to the wall, Dean practically tearing his shirt from his body and running his hands all over Cas. Cas just stood there, frozen, before deciding to at least try and enjoy it. He slowly moved his hands across Dean's back, running them under his shirts, before pushing the shirts to the floor with an approving noise from Dean. If Cas seemed quiet or unresponsive, Dean didn't notice, taking his own pleasure while Cas merely played his part robotically, not feeling anything. There was an emptiness inside that no amount of physical closeness with Dean could fill.
On the outside, their relationship looked wonderful. They both appeared to be very much in love, running hands across the other's arms when they walked past and sitting in each other's laps when they watched TV. But it was all just an act – Cas didn't really love Dean, not in the way Dean wanted to be loved, and Dean didn't really love Cas, or he would have noticed his partner's discomfort. Besides, those who truly loved their partners didn't sleep with anyone else, and Cas knew that Dean was still sneaking out in his baby to pick up girls – they shared a bed now, and sometimes Dean would crawl in ridiculously early in the morning, smelling of cheap booze and perfume with a guilty look on his face. Cas always pretended to be asleep, but in reality he still had trouble sleeping, and he was lucky if he could sleep for four hours a night. Remaining asleep while Dean was moving around would have been virtually impossible.
They were both broken, and being together couldn't fix that. All it did was make the problem worse.
Sam wasn't getting better. Every day he was the same as the last – he would remain in bed until the afternoon, before dragging himself up to eat, shower and watch TV, then he would crawl back in again before it even got to evening. His coughing reverberated through the bunker at strange times of night, and he looked like a shell – the same way as Cas felt. Cas knew that he needed urgent medical help, and he suggested this to Dean, but Dean insisted that Sam would get better. He just needed rest, Dean claimed. Then he would be fine.
When Sam died, it wasn't a surprise to Cas. He had almost expected it after Dean refused to get help. He mourned, as he was supposed to, but he had long stopped truly feeling anything, so once again his sadness was an act. Dean gave him a proper hunters burial before going out, to try and forget what had happened. Cas didn't see him for three days – curing those three days, he slept better than he had in months.
When Dean did return, he was drunk and angry, barging in and pushing Cas out of the way. Cas had felt a flicker or emotion for the first time in weeks – fear. He was afraid of Dean, of what he might do. He pulled Dean into bed and tried to soothe him, but nothing was working, and eventually Cas just gave up, lying there and leaving Dean to his fury. There was nothing that he could do – not when he was so dead inside himself.
It was never meant to end up like this. If the trials had been real, if they had worked, and Heaven and Hell had been shut forever with no-one dying or getting hurt, things would have been different. Dean and Cas could have ended up together happily, Cas still with his angelic powers and the profound bond that drew him to Dean's soul. There would have been no fighting, no drinking, no hiding the bruises and putting on a show of happiness to everyone who visited. Everyone thought that they were doing fine, holding each other together – instead they were breaking each other apart.
Their lives were twisted, warped, broken messes, hidden behind a portrait of love. A photograph of smiling faces that didn't show the knives held to each other's backs. A painting of a calm pool that didn't show the serpent hiding beneath the surface. A stupid, ridiculous, wonderful caricature of intimacy.