I've squandered all these years.
Spoilers for the first quarter of the manga, and the midpoint of both anime seasons. The title is taken from the 31 Days theme for October 27, 2009.
It was hard, of course, not to be a bitter about the way the thing that was supposed to be the two of them had fallen apart, and easy – only too ridiculously easy – to hold on to the hurt, to bury it deep inside of his bones and keep all the memories close, collecting them like stones and stuffing them into each and every one of his pockets. Unfair of him, perhaps, but he was tired of being the one who had to bend all the time, for each and every single matter that demanded his attention. He was a good soldier and an even better dog of the military: because of that, he figured that it was his just reward, allowing that one painful indiscretion. Painful, at least, for the man whom all of his longing and self-loathing and sorrow was directed towards.
Nevertheless, he stayed close at hand, listened through all of those phone conversations, showed up every single time the guy happened to be around and raring for a drink at the usual place. It became easier, with time, to balance out the harsh demands of his heart over being jilted with the need to be civil enough to keep himself from driving his friend away completely. He lost it a little whenever they had both had too much to drink (he's still human, after all, in spite of the fact that he's a walking flamethrower), but as a general whole, everything went along swimmingly. Soon, he became very good with staying in the presence of the wife for more than six hours without wanting to turn around and flee. Soon, there were times that he became so comfortable that he had to remind himself of the weight he had chosen to carry, a means through which he could keep himself from getting hurt all over again.
As he stood in front of Maes Hughes' grave, however, Roy Mustang thought back to everything – to all those years spent quietly punishing the man for failing to love him – and thought briefly about a certain set of notes that he kept under lock and key, papers containing a transmutation circle ten times more complicated than the one etched unto the back of his gloves, a complete list of the many raw materials that make up the body of a man.
He realized a moment later, though, as it started to rain inside the quiet confines of his own thoughts, that maybe all of that, too – the agony, a new and deeper sort of regret to replace the kind that he was accustomed to – was exactly what he deserved.