We simply confine our sexlives to those people we are having sex with. We don't flaunt it, even tho there is a titillating aspect to that (having people KNOW I enjoy BBC was quite sexciting for me when I was active), involving unknowing unparticipating family is simply a bad mistake and an error in judgement. Same with your younger ones. Just not something they need to know about.
If someone is visiting, and family shows up, you treat that visitor like you would your family while they are there. And jump their bones the second family leaves.
Curious, does your family show up unannounced on a regular basis? I suppose if they live locally, that is a possibility but we live hindreds of miles from our nearest relative so the only people that would do this are my parents, who think nothing of driving 900 miles unannounced and ask when they get there is we "mind if they visit a while"........hubby HATES that. J (the wife)