It was supposed to end as a oneshot but I hadn't seen OP's request for a happy ending. So I continued. No happy ending YET, but I promise there'll be one.
don't waste your touch, you won't feel anything
or were you sent to save me
i've thought too much, you won't find anything
worthy of redeeming
- AFI
Everything might break or tarnish or rust, but not Alfred - Alfred was the one bright thing left in Arthur's life.
Arthur could remember the very first time he'd met the American boy - the tiny little thing he'd been, all big blue eyes and pink cheeks and a mop of tow-blond hair. He'd buried his face shyly in his mother's shoulder as Arthur came closer, peering at the first child he'd ever met who had been smaller than himself. Arthur had adored baby Alfred on sight, had made gentle overtures and coaxing noises - like his mother with injured birds - offering toys, a scone, a sippy-cup of milk to share - until Alfred learned there was nothing better than to crawl into Arthur's lap for cuddles and kisses.
That was how they grew, loving and sweet and adoring each other, Arthur the protective doting elder, Alfred the worshipful, wide-eyed younger. They were each other's suns, the center of the other's universe.
And then Alfred moved away - weeping and promising to return, but he left. And by the time Alfred returned, everything had changed.
Everything had changed. His sweet gentle mother had grown aged and gray under the burdens of life and loveless marriage, withered like a wildflower in winter. Sweet and gentle to the end to her only son, even to the stepsons that were none of her blood but whom she loved nonetheless, but there was an end. And the house was bereft of her, and much the worse for it. Arthur's elder half-brothers had loved her, and resented that she had loved Arthur the most, even if she had never shown it. They shunned him. His father ignored him. And Alfred was gone.
All sweetness and gentleness had left Arthur's life by the time his mother had died; all sweetness and gentleness inside Arthur himself followed suit shortly thereafter. By the time Arthur was in his teens he was a hard-drinking, chain-smoking fuck-up (his own words) who fought and fucked at the drop of a hat, sometimes both at once - he lied and cheated and stole - forged signatures and vandalized buildings - hotwired cars just to take them for drunken joyrides.
And then his father noticed - noticed only because he thought it might reflect negatively on him and his business. He hauled Arthur into his office, gave him a few cutting rebukes - as cool and impersonal as employer with employee - threatened to give the few pretty things Arthur's mother had left for her son to his half-brothers - and shipped Arthur off to boarding school, the esteemed Hetalia Academy.
Arthur quieted, under the threat, but did not really improve. He did appear to. He was top of his class and president of the student council. But he still smoked and drank. Instead of stealing and vandalizing, he traded blowjobs and the use of his ass for grades and favors.
And then Alfred came back into his life. Taller now, tall as Arthur at first, and then taller still after a little while - baby-round face beginning to angle into maturity - broad-shouldered and leanly muscled - but under the oversized leather jacket and the glasses he was still Alfred all over, sun-bright and sky-eyed and always smiling. He still bounded to give "Artie" hugs and cuddlings, he still brightened up like a sunrise just to see the older boy, he still smiled and wanted to eat with Arthur and watch movies with him (And he still loved Disney - openly, at that) and wanted to make Arthur watch him at his games, just like a child yelling for his mother to watch him do something impressive - in short, he wanted to spend all his time with Arthur, and wanted Arthur to spend all his time with Alfred.
So of course Arthur had to pretend the overgrown child was an annoyance instead of the only dear thing left in the world to Arthur; he had to wriggle uncomfortably out of embraces and to snap irritated dismissals; he had to shove Alfred away and scowl until his thick brows formed a single angry unbroken line.
Alfred was too pure, too bright and beautiful for the ugly, sticky world Arthur lived in. Alfred did not deserve to be made fun of by the likes of Bonnefoy and Braginsky, who would coo and smile under eyes as cruel as stone; and Alfred could not learn what Arthur did with them and the others in the darkness of locked rooms, or Arthur's heart would break as Alfred's trust in Arthur would; and Alfred could never, never, thrice never, know what Arthur wanted to do with Alfred - to Alfred - because what Arthur wanted was worse than all of the rest put together. He had been thoroughly ruined and corrupted by what he'd done and what he'd let others do to him; but he hadn't realized how much of a degenerate he had become until he looked at Alfred and dreamed of things he never should have dreamed about his "Alfie".
Therefore Arthur treated Alfred mostly like a stray dog, and Alfred only laughed and continued to bounce around Arthur with only occasional flickers of hurt confusion. He reacted to Arthur's angry behavior exactly the same as if they had been endearing, friendly actions, and aloud Arthur cursed him for being too stupid to leave Arthur alone, and silently loved him all the more for it.
Until, of course, one day, Alfred had discovered what Arthur really was after all.
Arthur had come into his office to see Alfred waiting for him, for the first time neither smiling or pouting childishly - just grim, unsmiling, his blue eyes darkened, jaw clenched so that Arthur could notice the line of it. Before Alfred had said anything, Arthur had known.
Flailing like a drowning man without a lifeline, Arthur had hardly heard Alfred's hurt, accusing tones - but picked out enough words to know his worst fears were coming true. He poured himself a shot of rum from his personal flask to strengthen himself, had offered some to Alfred.
He had nowhere to go, nowhere to escape. His head was spinning and his chest felt hollowed, caved in. Alfred was in front of him. Alfred knew. He knew!
Sex was a coping mechanism - something to barter with. Arthur gave people sex - people gave him what he wanted. He offered it to Alfred. He wanted Alfred. He crawled into Alfred's lap, purring, lapping at the line of his jaw, nipping at Alfred's earlobe, shoving the jacket off those broad shoulders and using Alfred's sloppily-fastened tie to yank (hah, he thought half-hysterically even as he did it - Yank.) the younger boy's face to his, so he could kiss him.
Alfred knew. It was Arthur's nightmare. He was kissing Alfred, pulling him to the couch, running his hands all over that sun-tanned, muscular body like he had wanted to since he had seen Alfred again. It was Arthur's dream. It was dream-that-was-wrong and nightmare-that-was-inevitable all rolled into one feverish moment.
He finished, Alfred finished inside him. Overwhelmed, Arthur stood up on shaky legs, dressed himself with numb fingers and a mind whirring uselessly like a wheel suspended in mid-air. He could not speak, he could not look Alfred in the eye. He sat down behind his desk, where he always felt most in control - the desk which was the one place he had never defiled - and in order to occupy his shaking fingers began to rifle through the papers left in his tray without once registering a single letter that was printed on them. He waited for Alfred to speak, for Alfred to begin so Arthur could reply, just like it always had been.
Instead, when he looked up, when he could bring himself to, Alfred was gone and Arthur was alone in the council-room.
He knew what Alfred must think of him now. He wandered through his days in a numb daze, unable to finish thoughts, unable to meet Alfred's eyes. Alfred was avoiding him too, he realized after a while, and he could not bring himself - coward that he was - to seek the younger boy out, despite missing him so hard it was a physical ache.
Alfred, golden boy of the Academy, began falling into the same trap that Arthur had long ago. He fought and he mocked and he skipped classes and practices. Arthur would torture himself at night wondering if Alfred - now that Arthur had defiled his innocence - found solace in the bodies of others. Francis had known what happened, somehow - went over to taunt Alfred or proposition him or both - and came back with his nose swathed in white gauze. Even that was not enough for Arthur to smile, nor when Gilbert appeared the next day with his arm in a cast.
"A rebel without a cause," Arthur had overheard someone saying, mockingly, "...probably on drugs or something."
Arthur blamed himself. He kept telling himself he would apologize to Alfred, make it right somehow - but then one day he heard that Alfred's parents were in the office, finishing paperwork, and that Alfred was leaving the school, and he knew it was too late.
He watched Alfred leave from his window, recalling how similar it was to that last time he'd seen Alfred back when they were both children, the last time he'd seen Alfred being bundled into a car to take him to the airport, just like now. But back then Arthur hadn't been hiding behind a window-pane, and Alfred had clung to him tearfully until the last moment. Back then Arthur hadn't been ashamed to cry in front of Alfred. Back then, Alfred had waved frantically to Arthur through the back-window of his car until the car was out of sight.
Now there was no tears, no waving, no goodbye hugs and no promises that Alfred would one day return.