Making fantasy a reality?

Unbelievably I already have my first question! And, no dipping toes into the water here. This is a bona fide, unadulterated (no pun intended. Well...okay. Maybe a little bit) baptism-by-fire type question.
The reader asked for my advice on the process of bringing a fantasy to life. Her fantasy is a two-parter. 1. to be with another woman. and 2. to be with multiple men at the same time. And she's looking for some thoughts on how to broach this subject with her husband/partner.

As I said, no bab...