What sort of relationship do you believe in?
I'm a total monogamy man myself. If a relationship is strong I stick with it through thick and thin. Unless there is cheating involved or other such terrible things.
What about you?
As a side note: If you are a monogamous person in a relationship that very rarely tries sexual encounters with more people I'd personally say that would classify you as polygamy, even if it was only once every 5 years.