Happy to help! I mean if you’re paying for it, you can require that separate space exists. You can’t require that she use it every night, but it’s there if she needs it. You could cloak it as “what if you have finals on different days and one needs to study later and one needs to get up earlier” or “if one of you gets sick, you will be glad to sleep peacefully.” But you really know it’s just to prevent disaster in the event they break up.