opinions on "Free Spirit" relationships?

so I have this friend who is into "Free Spirit" relationships which is different than polyamorous! Basically he is in a relationship with 2 girls...maybe more...all the girls know about each other and don't care and all the girls also sleep with other people. so it's completely open. I'm curious just to know what you all think of it?

personally I see nothing wrong with it and it sounds kind of appealing! like...it's a relationship that I would be okay with (if I wasn't already married! lol!)