Anniversaries are hard, always have been.
It's never been October, when it comes to Erik. October is for Raven, who left in 1962 and never came back (save for those few weeks in 1974, which hardly counts, for that wasn't the Raven he had known, and she left again as soon as she was able).
No, with Erik it's always been July, for it had been July when they met in the water, so long ago. Charles has hated the summer ever since 1963, when he realized July seventeenth would mean something to him going forward. Perhaps even (though he hoped not, then) for the rest of his life.
1963, 1964, 1965, 1966, 1967, and summer came to mean Sean would go home to his mother, to help watch over his younger siblings while they were out of school. Summer came to mean brooding and sweating and brooding some more in a house that much emptier, with so little to do and too much to think about. Summer meant paying a little too much attention to the radio, trying to make out if the CIA had gotten their hands on Erik yet, secretive as their manhunt was. Summer meant never going one single day without arguing with Erik inside his head, even if he'd done well and put Erik out of his mind for the bulk of every other season.
The worst summer of them all was the summer of 1970. The previous year, Charles had wondered if seeing his students leave the next June would make him plummet even further, even harder than he usually did. But his students had left in December, not to return, and Sean and Alex had been deployed in January. It had been he and Hank, alone in that house for six months. By the time they received the phone call from Sean's mother, Erik had been in Charles' head again for weeks, picking at him, telling him his failure was because he had been naive, he had been stupid to think it would ever work.
The next few summers weren't much better. Neither the serum nor the drink quite worked to drown out that voice, quell those arguments.
They didn't improve until he decided to try again—until, faced with the mutant children who'd been held and experimented upon in the same facility as Raven, he had no choice except to get back up. Later, Charles would think it was so funny—faced with Erik again, he'd barely even paid him any attention, too intent on making sure everyone else was all right, that they hadn't left anyone behind in the building before Erik brought it down.
The summers varied, in the years and decades that followed. Some were so busy—planning, recruiting, conferences and meetings; the children might get the summer off, but Charles never did—that he hardly thought of Erik at all except for that one day, and sometimes didn't even realize why until the eighteenth or the nineteenth, after it was over. Others were still busy, but somehow still resulted in Charles continuing to think about Erik underneath everything else, a constant irritant.
It's July seventeenth again, and Charles has hated summer, hated this day for so much of his life. He's been dreading it this year, too, not knowing what he'd have to say to Erik about it—Erik, who's slept beside him every day since they found him half-frozen like a fool six months ago. Erik, who's sleeping beside him now. Erik, who hasn't spent these last fifty-odd years counting the way Charles has. (Or maybe he has. Charles hopes not. He can't imagine how bad those three summers Erik thought he was dead were like, even without that clock ticking and reminding in the background.)
It's July seventeenth again, and things in the world are worse than they've ever been before—for mutantkind as well as their human counterparts, if the latest reports on Sentinel activity are to be believed. It's July seventeenth, and even Charles has to admit that any hope that remains must be a very grim hope indeed. It's July seventeenth, and Erik being here doesn't mean much, not in the grand scheme of things—but it means something to Charles.
At the very least, it apparently means today is going to be a good day.