Nothing can substitute for both you and your friend asking your wives how they feel about the idea. In fact, that's exactly how I'd ask Mrs. Alura:
"Sweetheart, how do you feel about fucking John and Mary Jones?"
Of course, we've been playing for over twenty years.
You might start by asking her how she feels about group sex, or recreational sex, or swinging. Be sure to ask a question that can't be answered by "Yes" or "No." Wait for her answer before asking the next question.
Many folks have written about success in bringing their spouses to this board and talking about it. We're all willing to help.
Mr. Alura