Dear Sir.
No one can dictate how you and your wife want to outlive your fantasy or lifestyle.
The trust and agreement must be between the two of you.
My husband and I are living a very similar lifestyle as you described.
We are very happy together and still enjoy sex together as well. Very much actually. Our QOS/BBC lifestyle on the side just gives us more pleasure on top of our more private sexlife.
We have very clear rules to avoid what you also described.
For us hubby is the only one planning what’s happening on the side. He decides 100% when, where and with whom. We are living in a Dom/sub. relationship with me as the happy receiver.
Personally I’ve been attracted to black men since I was young and hubby likes to watch. Sometimes he interacts, but it’s 100% up to him. He’s not afraid of touching a black cock himself, but his main thing is to enjoy all the planning and the build up and to challenging me, and I still love him dearly.
So long story short. To us it’s possible to live this lifestyle without any problems.
Hope it covers some of your concerns. Please feel free to ask if you want me/us to update anything.
Hugs from Denmark