I think people can do whatever helps them find happiness. Me personally though, I couldn't do it because the jealously would eat me alive and I like the idea of being someone's only one.
I have no problem with it when other people do this. As long as they're happy!
I couldn't do this, it's not for me, I think it's only natural to be jealous if you're really in love with someone and that you don't want to "share" the person with others.
not for me. never will be for me. the concept of an open relationship disturbs me personally enough on it's own, let alone having a third person in there being committed too.