Review Detail of mooneless in My Beloved

I only read to chapter 4, im a little confused. is this love story ******? Are not the ML and FL from same family? And if they are not from same family, its still kinda weird. The FL grows up whit the ML as her brother, but they end up togheter as a couple... just becouse they dont chare blood dosent make it less disgusting... Could someone maybe correct me if im wrong? im putting this novel on a breake for now, im not very much into romance bether sister and brothers. Its like finding out im not blood related to my brother irl and then start having romantic feelings for him... wanna puke just thinking about it.