I would definitely have a problem if I saw my man doing something for a swing partner that he wouldn't do for me! Now if I didn't like it that would be different and I would tell him to go for it.
As for keeping up with whats happening in the other bed or next to us, we don't have a problem there, we both tend to work at our own speed and don't feel the need to be doing the same things.
This thread reminds me of a situation that occurred many years ago where we had met this couple and we had adjoining rooms, well the husband of the other couple saw his wife performing a BJ on my man and he flew off the handle....didn't even wait to leave before he started in on her, because she would not give him BJ's at home. An experience I never care to relive again! Needless to say that was the first and last time we saw them
P