I find it very curious that personality traits that MOST people possess, and are common to monogamous relationships as well, are being attributed solely to polyamorous people.  Comments like:

fear of being fully known (masking fear that one is ‘bad’, deep-down)

This is a characteristic of jealousy, the fear that you are not “good” enough or that if someone knew the true you they wouldn’t want to be with you.  So you “keep” them close through jealous actions such as not letting them experience others in social situations without yourself present or cutting your partner off from friends and family; anyone the jealous person sees as a threat to their happiness.  The protect themselves under the guise of “protecting” their partner.

In my experience many monogamous people will talk to me about sexual and relationship issues that they won’t talk to their partner about because they fear being rejected or their partner geting angry, jealous or otherwise hurt.

One common trait of many monogamous relationships, and one that keeps counselors and therapists in Mercedes and million dollar homes, is that people can’t be fully honest with their partner about their wants and needs. For instance when they talk to their partner about their sexual fantasies their partner reacts negatively with the “what, I’m not enough for you?” or they fear being viewed as perverted or wrong for having that desire. If I had a dollar for every time I’ve heard of a wife or girlfriend wigging-out because their partner brought-up a fantasy about a threesome or some other sexual act they don’t presently do, I’d be a very rich man.

For the most part polyamorous people don’t fear this since part of having a variety of partners is you and your partner’s acceptance to recognize and admit that there are just some things they can’t do or have no interest in doing, but they are also not threatened by someone else’s ability or desire to do so because they know that they are just one part who their partner is, and no way does it define who they are in whole.  Therefore they know their partner isn’t going to leave them just because they don’t have an interest in say BDSM, and someone else does. What they can and do offer fulfills just as large and important a part of their partner as someone else does with something else, whether this something else is an interest in photography, art, bird watching, golf, or bondage.

This doesn’t mean that polyamorous people never feel jealousy, it simply means they manage it well through open communication and respect for each other.

fear that one might become emotionally dependent on one partner and then lose them and be unable to recover.

This goes back to the general perception that because you don’t have a “one and only” that you can’t commit for whatever fear of commitment you may have.  Anyone who’s been close to a truly polyamorous person (not just one saying they are to get some strange) will tell you that commitment is THE basis behind polyamory. Believe me, losing a long-term partner in a polyamorous relationship is not any easier than losing one in a monogamous relationship. My wife was devastated for months when she and her other partner broke-up.

fear of missing out — that the grass might be greener in unexplored meadows.

Here you’re confusing the typical monogamous idea of stringing someone along without full commitment because something “better” might come along with a polyamorous relationship. The whole idea of polyamory is that everyone is unique and that no one partner is “better” or more important than another. You’re not looking for something that might be better; in fact the polyamorous person recognizes the uniqueness and specialness of each person in their lives and they cherish and celebrate the different dimensions those traits of their partners bring to them.

In short, unlike in a monogamous relationship, they aren’t throwing away one good relationship just because someone that adds something different and momentarily more interesting to their life comes along. They add it to their life like adding another Lego to the block.

fear of not being ‘enough’ for one partner.

This goes back to my first point of jealousy. This is primary characteristic of a jealous person, and polyamorists for the most part are not jealous people or they couldn’t be polyamorous. Polyamorists know they are just what their partner wants or their partner wouldn’t be with them. Why? Because the door is open for them to leave if they want and they don’t. So obviously you’re good enough, you’re smart enough, and gosh darn it, your partner loves you.

like fear of being completely honest about other relationships, an irrational feeling that one should hide them despite loving evidence to the contrary.

Ah, this is not a trait in of a polyamorous person. Polyamory is all about the naked truth and not hiding other relationships. Polyamory by definition is: the practice, desire, or acceptance of having more than one intimate relationship at a time with the knowledge and consent of everyone involved.

In most polyamorous relationships everyone involved in the relationships are at least friends even if not lovers. I have always been friends with my wife’s other partners and we hang-out together, go to car shows together, go to BBQ’s and function at friend’s homes, even at our non-polyamorous friend’s. My wife’s partners are very important to me because they are important to her, and visa-versa with her.

Less than full disclosure and being completely honest about other relationships is not only less than polyamory, it’s closer to cheating or having a “don’t ask, don’t tell” open relationship.

it has been rare for me to meet a poly person who does not identify as having ADD, and somewhat rare to meet a mono person who does.

This is a rather generalized statement since ADHD is far more prevalent than polyamorous people are, as such there are many, many more monogamous people who are diagnosed as ADHD than there are polyamorous people.

Overall, as others have said and I’ve seen in my own life, the polyamorous people I know are highly educated and thus usually have white collar careers in management or work high tech fields, and are very introspective, which you pretty much have to be to have an open relationship. Nothing can be taken for granted because open relationships take a lot of honesty, selflessness, communication, understanding and self-confidence to work. In fact, they are a lot of work. Polyamory is not for someone looking for the easy road or for someone that isn’t willing to work at a relationship, much less a couple of relationships.