You’ve been together for two years or so, both in sixth year of Hogwarts

You’re in your dorm in bed and hear talking outside your door

It’s Mattheo. He’s talking gently to someone

A few seconds later, there’s a knock on your door

Your 6ft3 boyfriend walks in with a girl, no older than 13 behind him

She’s been crying and looks a little panicked and spooked but you recognise the familiarity between them. The girl having raven curls framing her face and big, brown eyes: Mattheo’s sister.