I prefer monogamy. I like the security and bond me and my wife have. Like any human (male or female) i am still attracted to other potentials, i just don't give a shit to pursue them.
Now, if by polygamy you mean marrying many other women(or men) then i would have to disagree. Those relationships, even if all agree before hand, tend to end with abuse both mentally and physically. Not always how you think. Please note i am talking about people entering serious relationships with multiple partners at once, not one person cheating on multiple partners behind there backs, not one person going through flings, I am not talking about old fashioned courting of multiple women(archie style). I am talking about straight up serious long term relationships with a group of people.
If one man has three wive or one woman has three husbands the odds of emotional or physical abuse rise amongst the three perpetuated by each other, and not the one.
This is because of jealousy, and if you think it's something created by religion i would like to direct you to the animal kingdom. Where males or females(depending on the group dynamic) beat the hell, or kill, one another for the mate. It is a similar situation with long term polygamy. The three try to get the most attention, the one only has so much time, the one that gets the least will become emotional hurt and may begin to sabotage or hurt the other two to get more attention. The more mates in the pot the more emotional, and possible physical, abuse could be perpetuated against the other members of the relationship.
The reason why we don't see this in swingers, in fact we might see the opposite with the two becoming more emotionally attached, is because in those cases the swing partners are not becoming emotionally attached. Its sex and all participants are aware of it.
That is not to say swinging is the fix all to a troubled marriage, as people vary and it could destroy said marriage if there isn't a strong emotional foundation.
Ultimately what one person chooses is up to them, and i don't really have a right to tell anyone if they are wrong or right. I have my preference, you have yours.
However from what i have learned, mostly about human psychological behavior, polygamous relationships don;t seem to have a strong emotional dynamic. If you, or someone else, is in one that works and everyone is happy by god power to you.
To me though it is just not worth it.
Edit:
If the word marriage offends you in anyway please feel free to interchange it with Union, Long term relationships or any other fancy word you'd like to use to label "People promising loyalty for long periods of time".