LOTS of imagination Marcus!
It helps that we have a large room, so we all have our own personal space-including the kids.
Even with the kids-bedrooms are personal space and everyone else knocks before entering. The kids aren't required to allow guests in their rooms either.
So-it works less awkwardly than it sounds-we just don't take guests into bedrooms that belong to someone else. The only 'complication' is that Maca and I choose to make one room 'ours' in use, so noone else is allowed in. But-he has another room to use as personal space if he has a guest and of course, if I want to be with my bf, I just go to his room.