They can never know
It's the weekend and a sunny afternoon, so the Thunderbird common room is deserted, well, almost. Merope is secretly meeting with her girlfriend Isolt.
Isolt smiled. "I think that we should share our happiness with the world, Mer."
Merope muttered, "No, my brother and father can never know. If they knew my whereabouts, then I might never be allowed to come back here. You don't want that to happen, do you, Issy?"
Isolt frowned. "Of course not, dear. What was I thinking?"
Merope said, "In the heat of the moment you forgot about the situation you saved me from. I wish that I could forget."
Isolt stated, "No, you don't really wish that. Every day here your magical abilities improve, but you can never forget where you came from. Your brother and father are what brought you here to my school and to me."
Merope pulled her into a hug and grinned. "You're right. I don't want to think of a life without you in it."