Most people these days are NOT marrying virgins. Your partner has likely experienced several different people before you married and I can only imagine the number of sexual partners before marriage is increasing with every decade. Even if you marry a "good" girl now in her mid 20s, I'm guessing she's had at least 5 to 7 partners. Maybe more. And increase this number if you marry a woman in her 30s. She's likely had some great and fun sex with some of these people and ones that gave her a great rush, especially for the first few times after they met.
My point is that these people will never be considered sexually exclusive to their partner because at some point in their lives they've had sex with other people. Whether you were there in the bedroom watching or not, it still happened. But if a lot of men actually think about this way it would drive them nuts, so they don't even try.
Most men that come along and marry a woman think they're the best lay she's ever had. But I'm sure a lot of women get bored and think back to past sexual partners. I think guys in this lifestyle might think about it this way and think that hey, odds are she's likely had loud and fun sex with someone before, why not let her experience that rush a every so often, only this time i'll be in the room.
What are your thoughts on this line of thinking?