The idea of sexual propriety is a fairly modern concept, honestly.  The Ancient Romans and Greeks had much more open-minded opinions toward sex.  So why is it that today we have such stuffy and puritanical views toward sex?  Well, "puritanical" is an early clue here.  We, as Americans, take most of our views toward sexual open-mindedness (or lack thereof) from the founders of our country, and the Western European culture from which they came.  During those times, and even today, many modern,civilized cultures have much more open-minded opinions toward sex.  Even the Cherokee Indians (the original inhabitants of this land we call home), had views outside the "one woman for one man for eternity" viewpoint on sex.

And monogamy is not the only idea I'm challenging here.  Other topics still viewed to be taboo (and even illegal in some U.S. states), are not "bad" in and of themselves, such as oral sex, anal sex, multiple partners, orgies, BDSM play, and swinging.  What happens between two (or more) consenting adults, fully capable of making decisions for themselves, should not be considered "bad" or "dirty".

Oral and Anal Sex - Many people find both of these to be wonderfully erotic ways to enhance their sexual experience.  In fact, many people enjoy oral sex or anal sex even more then vaginal intercourse.  But, by labelling these as taboo and wrong, we have just alienated the entire homosexual population.  Just because they prefer a method of enjoyment that is considered taboo, does that mean they should be denied sexual gratification?  I don't think so.

Multiple Partners, Orgies, and Swinging - These may sound like the same thing, but their not, entirely.  By multiple partners, I am referring to when one or the other people in a relationship has sex with people other then their partner.  I am not referring to cheating here.  I am referring to an agreed-up arrangement where one or the other partners is allowed to have sex with other people, under pre-arranged conditions (that BOTH partners in the relationship must agree on).  An orgy is when three or more people engage in sexual relations at the same time.  Swinging is when two or more couples "swap" partners in a relatively controlled setting, usually.  All of these are viewed by many as another wonderful way to keep the sexual fires burning in a relationship.  And, more times than not, both partners will find that it enhances their sexual relationship with their partner.  However, it must be noted that open communication between both partners in the relationship is absolutely necessary and critical for any of these situations to occur in a manner that does not destroy the relationship.

BDSM and Kink Play -  Long viewed as very underground and extremely taboo, bondage play and kink play are becoming much more mainstream than ever before.  Of course, there are still those on the extreme fringe, who push the very limits or people's sensibilities, but they are the exception, rather than the rule.  In reality, bondage, and other control games during sex are no different than many situations in real life.  At work, home, and in social settings, often someone is in control, giving the orders, and others are following them.  Many people find this dynamic to be yet another great way to push their sexual gratification to new heights.  

I'm not necessarily saying you should try any of these methods to enhance your own sex life.  I'm basically saying that there may be ways to enhance it, if you just break down some of the mental barriers that you have put up concerning what is "good" and what is "bad."  Basically, if it feels good, do it, and if it feels bad, don't.  But, there should be no limits between two (or more) consenting adults regarding what is acceptable and what isn't.  The only barrier is that neither partner should ever attempt to push the other beyond whatever limits they have.  So, have a serious talk with your partner about their fantasies.  You might find that they've been hiding some fun-filled ideas that match your own, and were just afraid to ever express them.  

Additional Note:   It's not something I usually devote much time to, because I assume that most adults have the sense to practice safe sex.  But, it becomes even more important when you get involved in activities such as swinging, multiple partners, and anal sex, that you use proper protection at all times.  Sex is a very good thing (one of the very best things), but no sex is good enough to die for.