No Matter What
Harry never really grew up. Which was fine, Tom is pretty sure. Maybe. He didn't really mind taking care of the younger man. He never has, even when they were just little boys and Tom was struggling to keep them both afloat in the orphanage, a demon's child and a "special " teacher's pet.
And it's not as if Harry doesn't occasionally manage a moment or two if surprising clarity and maturity, lucid poking through his craziness for a mere fraction of time before he's back in five year old seer mode, speaking in simple broken sentences about things that seem mundane but later reveal themselves to be serious. Like one day when he asked Tom if he was feeling tired after work, looking surprisingly shrewd for a second, then before Tom could reply he dropped the bomb that there would be a second world war and gave Tom the puppy eyes for no apparent reason, before wandering off to curl up under the kitchen table, one of his favourite spots to hole up and get lost amongst the visions.
(Tom, at the time, was not sure whether to be concerned about another war or amazed that he still even fit under there. Even if his husband was still more or less a child, he was a full grown man, albeit a bit on the small and fragile side, and yet he always seemed determined to squeeze himself into nooks and crannies, as if he was still hiding from the world after all these years.)
Still. Even if it was supposedly fine, sometimes being married to someone with the mental capacity of a kitten was endlessly frustrating, in the strangest, saddest of ways.
Because what bothered Tom wasn't that Harry wasn't willing to help Tom, (he very much was, Harry sometimes seemed to essentially be a housewife for all his dedication to doing all of the household chores.) or that he was still not the talkative type. (He absorbed words like a sponge, but let them out like a very extremely slow hour glass.) It wasn't even the fact that sometimes Tom came home and Harry literally couldn't remember him.
(It had stung horribly the first few times, but after a few years of coming home to blank eyes and a tentative "...dad?" (Apparently their resemblance of one another had only grown with age) he had grown used to having to reintroduce himself to his own husband. It helped that he had acquired a pensieve just for those occasions.)
No, it wasn't any of those things, as much as they hurt him or bothered him or didn't. What annoyed him more than anything else was that, when Harry hadn't grown up, he lost the excuse of "he's only young. But he'll grow up."
Harry, Tom had to face it now, would never really grow up. Which was fine, Tom was pretty sure. He still didn't really mind, and doubted he ever would. He loved Harry just the way he was: birds nest hair, expressive killing curse eyes, penchant for spiders and rock collecting, constant mumbling and helpfully handing out things a person wouldn't need until days later, hiding in dark spaces, and all.
He just wishes that he could at least know that, when Harry gives him those big green puppy eyes and mumbles that he loves him before spouting random facts about next weeks weather, he could know for sure that the other actually knew what he was talking about, and wasn't just a scared kid trapped in an adults body, trying to please the only reliable figure in his life.