Armour
I almost ended up writing this as gleeful d'Artagnan with his pauldron and fondly irritated Constance, but no, these two idiots must forever ruin my life instead.
"Sometimes I swear you love that doublet more than you love me, I doubt you would even remove it if I asked you."
It's a symbol, and they both know it, just as they both know she's not really talking about the doublet itself; blue leather, silver buttons, fleur-de-lys pauldron fastened at the shoulder, all marking him as a Musketeer. They make him more than the drunken sot he'd been, more than the naïve young comte who'd been a fool for her, and if he strips those things away at her prompting, then what will he be – what will be left of him?
A man; a man and nothing more, and the man he was has been broken for so long that he fears what he might see now – even when he has seen that he can be more than broken, dares hope once again, but if he sheds that armour and lets her in then he may find the truth to be nothing of the sort, find that he is still just a shadow of a man. He must not, cannot, does not dare, and yet the part of him that leaned into her blade long ago in the château in Pinon aches to do just that, not to learn whether there is something beneath the leather but because he is tired, so tired of all this fighting, her and the past and himself alike –
He dares not, and yet his hands reach for hers, draw them to his throat, where the first button closes; his voice is harsh as he rasps out, "Then don't ask."