I think there is a certain idealism that comes along with polyamory that can be misleading and dangerous. I myself do not like it, would never engage in it, and would worry deeply for anyone that I was close to who was dabbling in such things. Certainly, if you would be happy doing it then go ahead and be happy doing it. But there is a reason this lifestyle is so intensely stigmatised, and there is a reason that the entire foundation is based on an archaic, patriarchal structure.
I do not believe in “one true love”, and I certainly believe that you can love more than one person. But to me, love is the exclusion of the rest of the world; it is a state of selective inclusion into the world of another, and I simply do not see room for another person in that.
Humans, specifically men, are not biologically primed to engage in monogamous activity. Women, however, are more likely to be suited for a monogamous lifestyle and will engage in deep pair bonding. Women are especially inclined to being able to bond with other women and would thrive together in a polyamorous situation, as this has been naturally selected in the primate species for millions of years.
Just as I believe that there is no “one true love”, I do not believe in someone not having a personal agenda or some level of selfish intent. I believe that a man who is skilled and charismatic can offer a woman what she feels she is missing and do it in such a way that she does not feel as if she is compromising what she deserves. And that man may enjoy making all of his 'wives' happy, but I guarantee he is enjoying making himself happy as well. What interests me is how easy it is to accept another woman into the relationship, but if the subject of another man broaches it is almost always out of the question. To be one of many women dedicated to one man is not equal, no matter which way you put it. You may have other women on your side, but there is an inverse sex-power relationship. In most situations, there is one man being loved by many women, and many women only being loved by one man.
A typical pattern is found in these types of relationships, where the initial honeymoon period will subside and more and more compromises and sacrifices are being made. The love, trust, and allegiance of one person is a lifelong struggle under the best of circumstances - having someone else to distract what is supposed to be a partnership will only complicate things.
After the honeymoon period in any relationship, love is not easy. And by love I mean the true love, the love that does last forever - or for as long as nature allows. You can be head over heals from the time you are 16 to 90, but none of it will have been easy. At times it will seem impossible, painful, incoherent, futile, and plagued with distractions.
My belief and my suggestion would be that if you want a love that lasts a lifetime, love yourself before you love anyone else, and only then find someone who loves you so completely there is no room in his/her heart for anyone else.
Now, this may not be the case for you and your relationship, and I don’t mean to lecture by any means. You can do what you want. But you should be aware of the risks and reality of the dynamic of that type of relationship before investing in it, because there simply is no way to spin it that does not weigh one sex over the other.
Do the research, do what feels best – but be careful, be aware, and be prepared for any consequences should they arise.
I'd also suggest looking into "swinging". What I find attractive about that is the ability to explore and enjoy and be intimate with other people, to have relationship - while keeping in mind the security and absolute faith in the love you have with one person. You are equals, and you are respectful and open and exploring the world as team.