As far as I still know from the spoiler summaries, her plan didn't work out as MC is going to leave this gathering without interest. And what does she do? Just sleep again with her ex. I mean yes he has cherry by his side, so he's doing it with someone else as well. But he's not into her that much while she totally is obsessed with him. So it's just weird that she easily fucks with someone else while being so much into MC.