He knows he loves her...
He knows he loves her when he sees her joking with Sirius, his best ever friend, and wishes he was the one who made her that happy. When he hears hair – prickling tales about her previous rebellious boyfriends, guys he knows he can never be as tough as. When he looks at pictures of laughing, teenage Tonks and feels that pang of jealousy, an emotion he's never before felt because this love? It's something new, almost foreign to him, and he still wonders if he's wrong to be thinking about her like this.
He knows he loves her when suddenly, after 15 years of sleeping alone, the bed feels cold and empty and no attempts at warming it work. When he finds himself trying to arrange his greying hair neatly over his bald spots with a comb because he knows she'll be at the party. When everything from baby clothes to sappy music reminds him of her and he can't help but savour the feeling, because it's the first time he's ever felt it – and ever will, or so he thinks.
He knows he loves her when, after a particularly bad day at the menial job he forces himself to attend because he so desperately needs to, she's there, smiling, and his heart instantly lifts. When he breaks down on his mum's death anniversary and realises he doesn't want anyone by his side but her. When he's missing friends, and school, and happier days and memories so badly it's all he can do to breathe and she's there, always there, a reassuring presence, a comforting hand, a light in the darkness he is forever engulfed in.
He knows he loves her when all of a sudden, just the sight of her large brown eyes, laughing with mirth, or the sound of her loud guffaw, or the warmth of her hand on the torn parchment she writes him love letters on, or the slightest whiff of the old perfume she constantly reeks of makes his heart beat faster and his breathing hitch, but he won't, just won't accept it, because he's him and she's her, and he will never be enough.
And he knows he loves her when he's suddenly always smiling for no goddamn reason. When her favourite song plays on the radio and he can't resist the urge to dance, something he hasn't done in so long he's almost forgotten how to. When he realises that despite the fact that he's been shunned by society so long that he's stopped believing in himself, maybe, just maybe, one day, she'll love him back regardless.
That's when he knows he loves her.
