He finds you crying and you know by the look in his eyes that he understands. It is your eldest son's wedding day and it is driving home the point that your children are not children anymore — they are adults, going off on their own and creating their own lives that don't involve you being there for every moment. Not that you've been around for Bill's every moment for a long time, but you bawled when he moved out, too, and this is like that all over again, but with more permanence. It is… all too real. Your youngest son is legally an adult already, planning to go off on a quest to save the world, your five eldest children are all moved out now, and Bill is getting married. To a Frenchwoman. You'll never see him.
You still aren't sure where all of the time went. It seems like it was only yesterday that there were toddlers running around and the burrow was just getting too small for your growing family. It feels so big now. It feels so different, so empty.
And you are so afraid. You are so afraid to let them out into the big bad world because there is a war going on out there and when they leave you cannot protect them. When they leave, you cannot keep them safe.
And it terrifies you. You cannot bear the thought of harm coming to any of them, cannot bear that one of your boys has lost an ear and that might not be the worst of it. You are so terrified.
Arthur doesn't say a word. He doesn't try to use falsehoods to comfort you. He doesn't try to say that it'll all be all right, because you both know that it might not, in the end. No one can know how this will end. No one can know what it will be like, with Dumbledore gone for good and a madman only growing in power every single day. It is an unknown, and you are terrified of that.
Arthur just knows. He understands you on the same intuitive level that he always has. You don't have to explain yourself or your fear to him. He takes one look at you and he opens his arms wide, letting you curl yourself within them. His embrace is warm and familiar and it feels like coming home.
It does not change anything about the outside world. It does not make you less afraid. But it makes you feel less alone, and for now, that is all you can ask.