I'm a widower, started swinging with my late wife as a Black couple. With no disrespect intended, many of you need to get the labels out of your head. Every participant is unique unto themselves, and so is every interaction.
We men feed our illusions of our 'studliness' and there is NO man who can outlast ANY woman if and when she is fully in heat, which is why more women are becoming more desirous of two men, if not gangbangs. Most of 'us' willing to watch at least in part is from knowing that, and some want to let go of being 'responsible' for satisfying her.
On the other side of the coin, most of the Black guys are being greedy and I doubt most tell their SO they play. This thread is a very, very rare time it has even come up in conversation.
My $0.02