Most days Darcy doesn't think about how old Bruce is. It just doesn't seem relevant. He's Bruce. So there's grey in his hair and wrinkles on his face, and sometimes he does things that none of her previous boyfriends have ever done, like open car doors for her or pull out her chair. None of that makes her think of the fact that he's closer to her parents' age than hers, though; it's just Bruce being Bruce. He would act the same if he was eighteen or eighty, she's certain.
But that's just most days.
Then there are the days like this. The Avengers were called out to put the smack down on Doom, and nothing in the reports indicate that anything out of the ordinary happened, but something obviously isn't right.
He's asleep now, curled up on his side with one hand fisted in the pillow and the other tucked under his cheek. He's asleep, but there's nothing restful about his expression. Darcy is careful when she settles under the covers next to him and tries to keep her touch light when she traces her fingers over his face. The lines by his mouth are deeper, the wrinkles at the corners of his eyes more numerous than they were when she counted them just a handful of days ago; he looks tired and old. This is a man who's been beaten down by life until he can't take it anymore, and then has it sucker punch him in the gut when he thinks it's finally safe to close his eyes for just a moment.
Darcy fits herself into the tense curve of his body and breathes in the reassuring scent of his soap and the faint chemical undertone he can never seem to wash away. He grunts and mutters something unintelligible under his breath that's closer in tone to the Other Guy than Bruce, but that doesn't stop her from draping an arm around his waist and slotting their legs together.
She and the Other Guy have an understanding. He's always there, lurking just beneath the surface, and she never forgets that at his very core he's still Bruce. She loves Bruce. More importantly, she trusts Bruce, which isn't something she was ever really able to say about anyone before Jane and New Mexico brought her into this crazy new life. She's used to having her armor up, uses sharp words and the occasional accessory as weapons to guard her heart as well as her body, but Bruce tears down her walls and leaves her completely defenseless. It should be terrifying, but instead it feels like breaking the surface after being underwater for too long and taking a deep, greedy breath.
So the Other Guy is there even now, visible in the set of Bruce's mouth and the furrow of his brow. Darcy kisses the hollow of his throat, where there's a pink scar that wasn't there just a few short months ago.
"Keep him safe for me," she whispers into his skin. "I know he does stupid, reckless things sometimes, but please keep him safe when I can't be there and bring him home to me after the battle's over."
And Bruce doesn't grow, he doesn't turn green, but there's a noise that rumbles in his chest that is pure Other Guy, and to Darcy it sounds like a promise.