Just saw this thread in passing. My Sub-Sluts marriage is based on this. When she and her husband first started dating she made it clear that she dated others and that she didn't like the idea of being exclusive. I think over the years its evolved into the Cuck/Vixen thing. I'm lucky to be able to take advantage of her kinky BDSM side, I'm not sure if my being black made a difference initially, I think it does now as I keep the process evolving and not boring!!