Responses
It hasn't been explained yet, but I'd guess that they're scared of the village going after them or just haven't considered it yet; they've both been conditined into heavy inferiority complexes and a false sense of duty/connection with the idea of this village and this land-- so it's not entirely unthinkable they don't want to leave regardless of how they've been treated. It's def something that could change further down the line, though.
Wait, so she and him can actually leave the village freely?! So why the heck didn't they just run away?! Or has it already been explained why they can't in previous chapters and i just don't remember?