> You can have a polygamous marriage all you want
>No, you can't. It's illegal in most states (see how the "Big Love" family had to move due to pending prosecution in Utah).
Yes you can, you can not however have more than one legal wife. You can marry wife #1 (marriage certificate) and this person will be the only wife the law cares about. You can then have any religious or whatever ceremony to marry any number of other women and you can all live together any way you wish. You can do this because the state doesn't care about the religious ceremony. You can not legally marry more than one woman, the women must know they are taking part in a polyamorous relationship and they can not be coerced into it. Again, the legal definition of marriage and what you call being married do not have to match.
As a side not, it is basically impossible to find what you are referring to with 'the "Big Love" family' since it appears to be a TV show as well. So I can't say anything about it.
> Not if you're male - sodomy is illegal in many states (despite a Supreme Court ruling that pretty much shuts them down) in the US, and many other countries entirely.
This is the best example of how the law and individuals differ. Legally (in the US), sodomy is defined as any sexual contact other than vaginal intercourse. Ever had a blow job? Congratulations, you could be charged. It has noting to do with being male, lesbianism would be charged with sodomy as well.
In the US, you can be as gay as you want.