I so understand that. Yes, I want my daughter to have an active sex life and I know she lost her virginity when she was 17 because she came to her mother. We do have that kind of trust. Would it turn me on to hear her husband or significant other pounding away with her in the next room? Yeah, I think it would.

If my daughter, at the age of 30 give or take a few years, wanted to swing I will be okay with it. I think swinging is an adult decision to make. I am glad I have not been placed in the position Charlie and Debbie were.

Semi-Related
 

I went to a BDSM/Swingers club in DC down by where the Nationals Stadium now stands. Unfortunately, the club is now closed due to high property values after the stadium was completed. One night, a date (Not a serious gf) and I decided to hit the swinger club. I had been there before when there was around 50-60 people milling about the club, and this night, there were only about 20. Odd, especially considering that this club was a converted warehouse and could easily host 200 and leave plenty of room to swing a cat-of-nine-tails.
After taking a walk around the main area and playspace, we heard some people up in a closed room having a wonderful time, then returned to the bar where the rest of the "crowd" gathered. There were about 5 couples there, including one stunning blonde woman in her early 20s. She was dressed modestly enough for the street, but well enough that showed off her tight body and perky tits. This blonde and her guy were getting very flirty with us and another couple, and we were all hoping to take it to the play area, untill she then sighed a huge sigh of grief and frustration.
"Sorry, guys, I still can't go up there."
"Why's that? I'm sure you'll relax once you go through the door"
"No, that's just it. I won't relax. My mom's been up there for the last 2 hours! She's doing it on purpose!"
Our jaws hit the floor. Her mom! That woman screaming in ecstasy some half hour ago, and aparently still up there is her mom?! She went on to explain her mom is one of the club's hosts, that she was visiting her parents from out of town, and that she herself has been a swinger for a long time, and actually started her experience in the club before. We didn't press her for details, but then about 10 minutes later, three people walk out from the play area. First, two middle aged men with huge grins, and then behind them a rail thin brunette in her 50s with a horrible case of freshly fucked hair. "Hey, hon, sorry i took so long"
In the time it took me to discreetly turn away to laugh at the situation, the blonde, her guy, and the other couple had bolted upstairs, went into THE SAME PRIVATE ROOM that was just occupied, and locked the door. I would like to say I got to hear her moan just like her mom, but she must have either held her tongue or had her mouth occupied for the rest of the night.