up to the most recent chapters which is like 10 plus chapters ahead, there really is little romantic development between jungyeon and his step brother sunwoo, obviously sunwoo is seriously crushing/falling in love with him but jungyeon is still very in love with his boyfriend and is only starting to see sunwoo as kind of attractive but thats pretty much it.
....
up to the most recent chapters which is like 10 plus chapters ahead, there really is little romantic development between jungyeon and his step brother sunwoo, obviously sunwoo is seriously crushing/falling in love with him but jungyeon is still very in love with his boyfriend and is only starting to see sunwoo as kind of attractive but thats pretty much it.