Being the Dark Knight was stressful, that was one hell of an understatement.
The moment Damian took on the mantle, he'd been both elated and worried. Elated because it was what he'd been trying for his whole life, but worried because of all the responsibilities that came with it. Not that he was scared, of course, he was the blood son, he was hella confident in his abilities. However, he also understood how difficult it was. The risks, the dangers that he'd have to face, the sacrifices that he'd have to make, he'd seen it all through his father, and none of those were ever pleasant or easy.
It took years to get used to wearing the cowl, and even then sometimes he still struggled. It wasn't unpredictable, Bruce's shadow was a huge one, and filling his shoes without making the same mistakes was hard as hell. Not to mention the fact that Damian was almost a literal carbon copy of his father (as much as he hated the comparison, they were similar to a fault).
There were nights when he'd overwork himself to the verge of collapsing in the cave, nights when he'd shut people out without a second thought, nights when he'd choose to take matters into his own hands and refuse any help, all because he felt like his effort wasn't enough, because he now wore the mantle and he had to. The young Wayne couldn't afford to disappoint anyone, especially himself.
Thank goodness though, in nights like those, he'd come to you—the love of his life, the moon of his dark nights. To you, he could show his soft side, to you, he could admit his weakness, to you, he could seek for comfort. And in a world where his demons wouldn't leave him alone, a world where the voices in his head'd always implore that he should be doing more, he'd always find himself running home to your sweet nothing, because unlike the people out there, all that you'd ever wanted from him was sweet nothing.
"Beloved." Damian breathed, pulling off the cowl when he saw you in the manor. God, it took all his self control not to jump into your arms right now.