Great question OP. For me, totally unrelated.
Well, actually no. They are related, but not in the way you'd expect. My wife knows I see industry girls. She doesn't want details, and we agree to boundaries, but she feels our sex life and my work performance are both better when I see MPAs. My wife and I are best friends and our sex is great. MPAs provide some fun and excitement, but never the deeper connection of a permanent relationship.