Disclaimer: Harry Potter is not mine for the taking.
H - Home
When he goes on missions at night, she can't fall sleep until he comes back home. She knows being an Auror is dangerous, extremely dangerous in fact, but she also knows it's what he wants to do, what he's good at.
And he is good at his job, one of the best (along with Harry of course), but that doesn't stop her worrying. Anything could go wrong and she can't sleep until she knows it went right.
She can't sleep until she knows he's home. Home and safe.
So she'll sit up at nights, wondering, reading, working. Mostly wondering. Wondering whether he's safe or not. If he'll come home.
She hates it. The waiting, the wondering, the worrying. She hates it.
But she loves him. And she knows he does it for her. To protect her, even though she would argue that she doesn't need protecting, to make the world better for the family they hope to have one day. And she loves him for that, and the love makes the waiting worth it. He once promised her he'd never leave her again and so far he never has done.
So she puts up with all of the waiting, wondering, worrying, because he always comes back. He'll tiptoe in the house, making as little noise as possible, even though he knows she'll be awake, Waiting. He'll smile contentedly before joining her and they'll fall asleep wrapped in each other's embrace. Together. Safe. Home.