I'm from Brazil and i'm definitely not white, though i have a lighter skin tone than most Brazilians. So i think i can help answer this question.
I always felt attracted to members of my family. that includes my mom, sister and cousins. It definitely helps that they are all pretty attractive and that i have no shame, lol.
Besides having a thing for incest, i also developed a cuckold fetish due to my first girlfriend cheating on me with a guy i hated when i was 15. He wasn't exactly a bully, but i still despised him. Imagine my surprise when i found out i actually felt horny when i thought of her kissing him and being more intimate with him than she ever was with me. That mix of hatred, horniness and humiliation was like an intoxicating drug, and i couldn't get enough of it.
From then on it wasn't much of a leap until i started thinking of him and other men i hated banging my mom and sister. Honestly, it didn't take long for me to forget about him and stop feeling bad about myself, but the fetish still stuck with me and here i am.
I'm 25 now, and i still jerk off to this fetish as much as i did back then. So my fetish isn't based on anything racial or on the size of my cock. I just like that feeling, that rush that comes with imagining someone i love being taken away/corrupted by a man i hate, and not being able to do anything about it.