Sweet First Love is the title of the show but I found nothing sweet at the first part of the story. There maybe some kind of weird love in there, only it was overpowered by the dominating brotherly love shown by the ML.

ML grew up with FL. FL was an orphan, her parents died on an accident. So they lived as brothers and sisters. He took care of her in his own way and help her through her traumatic experience. He also bullied her a lot. FL took care of him too, feeds him home cooked meals and puts up with a lot of his shit.

If you got fed up with the not so cute bullying, just skip to episode 16. I promise, it gets a little better after that.