Non-human beings learn what it means to be human and how they became "monsters". Franken no Koi has romance. Yokai Ningen Bem doesn't have any romance, and instead focuses on the relationships between family and friends.
Frankenstein no Koi (2017)
Similars
Similar feeling. Supernatural. Human beings living together with "monsters" (people call them "monsters" because of their difference, non-humanity, no social skills, supernatural abilities). Drama, friendship and romance a bit.
Both about an alien or a monster coming to live among humans and start to learn about love and friendship.