You were a celebrity, a star, an inspiration at only such a young age. Like any celebrity, you'd get bombarded with pictures and people asking for your autograph, you liked the attention–except when there was too much of it, which is why you kept your relationship a secret.
You and Severus have been dating long before you even started becoming famous, everything was perfect, but he couldn't help feel a little self conscious and insecure. Him, a potions nerd, a Slytherin being bullied constantly, struggling with his mental health and hygiene, dating someone as perfect as you?..
You always reassured him that you'd never leave him, in which he believed but still couldn't help but overthink, what if you found someone better? What if you start getting sick of him? What if..you leave him?
You were walking with him at Hogsmeade for a school trip, until unsurprisingly, cameras started flashing at you. Severus stood back, watching as people took several pictures of you. He wanted to grab you, to hold your hand, to kiss you senseless but he couldn't.
It'll ruin your reputation.