You should read 100% Perfect Girl. The description doesn't do the story justice. The ML and all other men that want the FL are seriously obsessive and ML is so crazy in love it makes him kinda crazy. But still a very romantic story.
You can always read the novel
I did, but the site where the chapters were posted shut down. The poster has a new website and was slowly transferring the translated chapters but it was still incomplete. I didn't get further past where the manga stops actually, but at least I read more.
I've been on a yandere male lead binge (there really aren't a lot of good or very sane stories with this tag tbh) so I fell upon this and I really like it. I probably wouldn't like it if I took it seriously but it's not the kind of story I could take seriously anyway.
Twelve chapters aren't enough to develop the story. I'm a bit sad that it might never get an ending.