In….cest…… is sort of a thing a lot of people find uncomfortable I think.
YEAH AND SEE a lot of people argue it isn't incest because of ectobiology or they weren't raised to know the other one was the sibling, so it's okay !!
in actuality it's like... imagine if you were 13 and you had a bunch of friends. great, right? awesome! then your father gets remarried to one of your friend's mothers. that friend becomes your step-sibling.
even if you had a crush on them before, since you're so young, you should grow past it. i know incest was common back then, and i know it really has no significant problems, but gosh. maybe it's because i have siblings but it creeps me out oh man.
heck, they spent three years on a cruise ship with their ecto-siblings. that's long enough for any romantic feelings to go away, right ??