Can't say I didn't see this coming In your other post, you made it out to be your husband that was pushing you in the direction of larger penises... but, thats neither here nor there. You want what you want, if he's fine with it he's fine with it, and what makes you happy makes you happy.
Fantasies are fine but if they are all consuming you may have a hard time with temptation. I've dated men of different races in my past and found that race has little to do with penis size on average. But if your fantasy is that it must be a black penis, and that it must be large, its your fantasy, its not hurting one... except probably the guy who'll never live up to your fantasy, but if he's happy then more power to you guys.