For me it would be all about the humiliation and the submission to the superior man.
I used to be just an average straight married white guy. My kink was that I did want to watch my wife have sex with other guys, white guys. But she would never do it. Then about 20 years ago I rented some porn I thought was going to be just mainstream white on white porn to jerk off to. It turned out to be mostly interracial. And I thought it was really hot. The next few times I rented porn it was mainstream white on white, and I found them to be kind of boring. So the next time I went to rent porn I was going to get something good. I looked at all the boxes, front and back. I was determined to find something good. About half through the little porn room in the back of the video store I found an obvious interracial video. I remembered how good the last one was. But thought I cant get that. I'm a white guy. I'm not supposed to like that, am I? That's what black men that like white women watch, right? So I checked out the rest of the movies. And nothing looked good except the interracial video. I looked at every thing again. I ended up making 4 trips around the room, trying in vain to find something other than the interracial video. But nothing would cut it. And I finally got the nerve up to rent it. It was even better than the first one. I tried one or two regular mainstream videos after that, but they sucked. I was hooked. The color contrast was hot. The men was muscular and with bigger cocks than their white counterparts. And the women seemed to get off more. They seems to enjoy the sex better. I could see a white woman do a scene with a white guy and she'd be ok, but then I could watch the same white chick in a scene with a black man and she'd be much more into it. It was obvious, the sex was better with black men. At this point I thought I was the only white guy in the world that was getting off to black men fucking white women. Until I got internet later in the mid 90's. Then I found out I was far from alone in my appreciation for how much better black men fucked white women than we do. Now I desperately wanted to watch my wife get fucked by other men, but not just any men, they had to be black men. But still she would not be a part of it. We ended up getting a divorce sometime later. My interracial porn addiction only became worse. I watched black on white, black on asian, black on Hispanic, and even some black on black. As long as a black cock was fucking a woman, I loved it. I remember times when I'd be with a group of guys, all white, and someone would put some porn on, if a scene would come on that had a black man fucking a white chick, someone would end up fast forwarding through because they couldn't stand to see a white chick get a good fucking from a black man. I of course was only interested in that scene. But at that point, if a scene ever came on when I was watching porn by myself, and a white guy was fucking someone, I would fast forward though. White guys fucking anyone was a big turn off for me. Then about 5years ago two things happened about the same time. I discovered cuckold porn, and I began to watch porn with black men fucking white trannies, and then eventually black men fucking white guys. For me the black cock was everything. Black cock was sexual pleasure and satisfaction. That was when I admitted to myself that interracial porn had made me bi. It did not take long before I found myself at an adult bookstore allowing black men to use me. Don't get me wrong, I still love women. And I could only ever have a relationship with a woman. But I do have a need to show my submission to superior black men. And now I could never be happy in a normal vanilla relationship. I could only be happy in a cuckold relationship, with my wife/girlfriend taking many black lovers, and me submitting and being humiliated by them. And that would include me eating their fresh load out of the woman I love's pussy. And should they want me to, I would gladly have her lover's disposition their load anywhere in me or on me they wish.