I think we would be in this dynamic. I'm not into the cuckold thing, but love the idea of a hotwife or being part of a 3some or more with her. I want to see, and hear, and experience everything else as she gets fucked by a black guy (or anyone that interests her). Participation would be the high point.
I never got to see my wife with her first black lover -- he was scared I might get jealous, and being bigger than him it could end badly for him. He could not be convinced it was not a problem. She had a great time with him. We had the most incredible sex all weekend after her first date. It supercharged us and we had great conversations as their relationship progressed. The second black lover was a 1 night stand at a conference -- very hot, but not participatory. She was really turned on because the 2nd guy hit on her quickly and really wanted her that night. It was the sort of thing she never had happen in her younger days. In contrast, the first guy had been a slow chase and seduction, building up until she just had to find out what he was like.