For me, it depends on the chemistry, and my mood at the time.
I have enjoyed one-on-one with married white women. I've told the true tale of one particular wife, a mature woman, who twice drove all the way down from Northern California to the Los Angeles area so that she could k!ll two birds with one stone. She came to visit her d@ughter in college, and to spend a night with me in my bed. She informed me about her d@ughter, but I'm certain her d@ughter knew nothing about me. I never had the privilege of meeting her husband in person, but we did communicate online at the outset. Kim, the wife and m0ther, would give her hubby a call in the mornings, talking quietly as she lay beside me in bed.
In other instances, I have enjoyed the MFM dynamic with a mature white couple, sharing the lovely wife in their marriage bed. The first time was a bit awkward, since I was new to the lifestyle, and it was the only time I agreed to being recorded ( video and still photos ) during sex. I still don't prefer that, but I did get used to it. The lifestyle kink is present in both situations, one-one-one as well as in the presence of the other spouse. However, I feel that the taboo kink is enhanced when the husband is in the room or in the vicinity, somewhere in the house. I've experienced the latter as well, when the friendly hubby courteously busied himself in his "man cave" on the other side of the house while I fucked his wife in their bedroom. Sharon was a much older woman, and our age gap was far more pronounced at nearly 30 years. So, that was a bonus kink that, once I made the adjustment mentally, became an extreme turn-on. If not for the long drive, that could have developed into a regular thing.
I'm in contact with another mature white wife who revels in playing independent of her mate, not even telling him any details about her encounters. There's no formal arrangement for me to even meet the husband, which is new for me. We'll see how it goes. But again, chemistry and mood. Both situations are uniquely enjoyable, One-on-One Fun, and Three's Company. But there's something special about watching a husband and wife expressing their affection for each other, demonstrating their secure and happy union by kissing and cooing, all the while I am raw-fucking the wife's wet, warm pussy.