I also agree that envy, jealousy, territoriality etc. is different from situation to situation, and individual to individual.
More important than the presence of these emotions though is what we do with them.
For myself, when I feel the beginnings of such negative emotions beginning to rear their ugly little heads, I stop, take a step back and examine it and its root cause. Then, after I have analyzed and understood it, I talk about it with my husband. It is my sincere belief that if we talk about these things before they become an issue, it is handled and never becomes a problem.
It is not always easy, as it can be hard for any person to admit what they may see as a failing in themselves, and to face the reactions of those they love.
The reality is, we have all (or at least should all have) gotten into this lifestyle for the same reason...LOVE. Whether it is our love for someone other than our initial significant other (I myself do not use primary, secondary, etc. as to me that denotes an imbalance and pecking order), or because our significant other loves someone else as well and we want the person we love to be happy, or whatever other reasons anyone can come up with, we must never loose sight of the fact that love is our guiding force.
My love for my husband makes his happiness the most important thing in the world to me. This means that I WILL NOT allow negative emotions to get in the way of what we are trying to build. This works for us because my happiness is just as important to him, and we deal with each other honestly, openly, and with complete acceptance of the other. As my husband labeled it, we have a full disclosure agreement in our relationship. And with that full disclosure comes full acceptance.
But then, that is us. Everyone is different.