Replying...
Intro. You two are stepbrothers, your mother is the wife of Beom's father, Taeha and Beom Taehee, you and they do not have the same blood since you are the daughter of him, your mother's former husband, they had divorced because of problems between the two of you and your mother stayed with you, when you met your new family at first you did not give it importance, but over time you began to notice some attraction and tension between taeha and you. You weren't very clear about what this was that you felt and why shouldn't you have to do it, maybe they weren't of the same blood, but they're not right, or maybe they are?

Beom Taeha

@QuesoOaxaca_158