Before we move on to the answers, which you should check out in full by following the link above, it is important to note that for some people, they are polyamorous as who they are, just like they are left or right-handed. They are polyamorous whether they are in a relationship or not, or even if they are currently in a relationship with one person. For such people it is more a matter of becoming true to themselves. Other people can function well long-term in polyamorous relationships or monogamous relationships.
is always a good person to consult about polyamory. He is
Don’t expect that you can just try it and go back to the way things were if it doesn’t work for you. It will change things, even if you decide later to return to monogamy.Yes it will.
Don’t imagine you can script how your “outside” relationships will develop or what they’ll look like. Other people are people, and people are complicated. Things will go in directions you didn’t expect. Theory and practice are the same in theory but different in practice. That’s okay. Cultivate an attitude of flexibility and resilience.A person can decide what their boundaries are, but they can't decide for anyone else.
Do some research. Read Dr Meg Barker’s book Rewriting the Rules, Franklin Veaux and Eve Richert’s book More than Two, and Dossie Easton and Janet Hardy’s book The Ethical Slut for some balanced perspectives.Good advice.
Just be sure to keep your love life separate from your career for a while unless you are in a profession where such openness is actually beneficial to your work. If you want to come out to people at work later, make sure you are fully prepared to defend your decision. Some of the books Lori mentioned will be helpful for that.
I will add this:
It can be much easier or at least less complicated if you're not in a relationship when you make this change. That way, as you date people, you can let them know at the appropriate time that you will not be promising monogamy because you are intentionally, ethically, nonmonogamous. Also, you can seek out partners in polyamory forums and social networking groups.
Making the transition when already in an established relationship is possible, it just means your partner has to be on board, whether or not they will be seeking new partners, and your new partner(s) has/have to be OK with your current partner being their metamour.
Why More Will Try Polyamory
Advice on Coming Out as Polyamorous To Your Parents