Unfortunately it appears that most women who are into "wittol" or willing cuckold relationships get into them via the husbands steering them toward it as part of their sexual fantasies. This severely reduces you chances of finding one that already has such inclination, but it is not impossible.
If you have a truly submissive nature toward women, you might look for lifestyle dominant women (NOT dominatrix) in your area, however, as with most women, there would be no guarantee that she would want to cuckold you, if that is your main fantasy focus. However, as you are identifying as "sissy" as well you may get lucky there if you are open to serving older women as many do enjoy being pampered and having "maid" service.
If you are employed and would be willing to help a white women that is pregnant with or who already has black children raise them with the understanding that she is still free to enjoy sex with others, you might advertise for such an arrangement and, with the economy as it is, you could very well find a lady in need of your financial and emotional support, not to mention help around the house and taking care of the *******.
Best of luck.