I was not prepared for actual incest

I mean, he's a doting brother to Di, but I've never considered him and Di to marry in the climax/finale of this story (neither does he anyway) so I'm all like, yeah this isn't incest, he's just very affectionate and that's cute. but first cousin... And if big brother cousin marries ugly's sister, and ugly marries cordelia, their children are practically siblings too. And here's cordelia liking her first cousin (though they're still kids so feelings could change)
Is it normal for in laws to marry each other? I don't think it is from where I'm from

I mean, he's a doting brother to Di, but I've never considered him and Di to marry in the climax/finale of this story (neither does he anyway) so I'm all like, yeah this isn't incest, he's just very affectionate and that's cute. but first cousin... And if big brother cousin marries ugly's sister, and ugly marries cordelia, their children are practically siblings too. And here's cordelia liking her first cousin (though they're still kids so feelings could change)
Is it normal for in laws to marry each other? I don't think it is from where I'm from
Ara-Ara, Unnies/Onee-sans, Mommies, I love them all