Universe: Clanverse (Yu-Gi-Oh!/Harry Potter)
She'd known really. She'd known all along that Yugi had only taken her to the Yule Ball because she'd pestered him. Had known that Yugi wasn't interested in her romantically. Had known that once he finally got into a relationship, he'd have much less patience for her.
Just because he would have had a harem in the past, didn't mean Yugi wanted one now.
It was a shame, because though she didn't want to share, she would if she could have Yugi, but Yugi didn't want one and that left her out in the cold and unsure of what to do with herself.