In all honesty, it all depends on the situation.
I mean, there is such a thing as polygamy, but it HAS to be wanted by BOTH parties. If only one person in the relationship wants it it becomes inbalanced and it's destined to fail. I know 3 couples that have been in open-relationships for at least a year, and they seem content with it. You just need to make sure to have your own rules set and things should work
