Magenta Dance by Ivana Skye

Sara Obsidian is having a great time with her boyfriends—all four of them. But when she develops a crush on another person, she starts to wonder just how many people she can handle dating.
And to make matters worse, the Red Rose Ball is coming up.
There, she might run into someone she doesn’t expect—and her harem might just be upended as secrets finally come out.