I think the concept of black "ownership" is predicated upon the woman allowing the bull to dictate (to one degree or another) how she is used sexually (and perhaps beyond that if she wishes to allow it). So if the bull decides to allow her and her husband/BF to continue to engage sexually, then there can still be a valid claim of "ownership," IMO. For many bulls, I can certainly see the appeal of asking or demanding that the cuckold remain pussy free. I mean, if you *own* the pussy, you probably don't want anyone else using it and it can be very erotic to ******* her to not allow her guy to have access to her pussy with his little cock.
The question of whether the woman wants her husband/BF to be pussyfree is a whole other question with respect to having anything to do with the "ownership" aspect of it all. But I know there are many, many cuckoldresses who, once they've been fucked by a large, powerful cock, simply insist that their men be pussy-free, at least from the PIV perspective (many still prefer their men provide them with oral services upon demand, of course).