Just erase that they are adopted. Or just remember that all of us in the world are cousins at the very least, incest has been a thing in the past and our long ago ancestors prob were products of it.
That’s what I do to my brain every time I feel icky about ADOPTED siblings. At the very least they didn’t actually grow up with each other, separated.
I also don't like them becoming lovers but to be fair he distanced himself since looong ago so i can see why they could see each other in non-siblings way. Ngl i never saw the sweet home alabama (even not share the same blood, their dads is in relationship lol so at least step-siblings) coming i thought they'll remain close siblings

Sweet home alabama