I was raised very conservative Christian, to the extreme of being a fundamentalist. I found the theory of polyamory at the time when I got into conflict with my religious background: my church and my family. Long story short: I found that the most important thing to me was to be totally honest and true to myself, and I stopped living and believing as the church and my parents told me to do - and was open and honest about my life and my thoughts. It was a rough time in my life as I ended up being excluded from both the church and my family. As I see it now, they could not take my honesty and wanted to have nothing to do with me.
Because of being honest I have lost a lot in my life, but they were people who did not love me for who I am - the sad part is that they are my biological family and all of the important people from my childhood. For the very same reason I have gained a circle of true friends; people who truly love me and cherish my attempts to grow as a human being. Some of them actually are biologically related to me; other members of the family who have been excluded as well.
So for me, the theory came first. I saw poly as a possibility to greater honesty in relationships. To me it was clear that all my relationships would be open in the sense of all communication being open as well as sexual encounters not limited to that relationship only. This I have stuck to in practice as well, and yes, have been pretty demanding a partner what comes to honest communication, freedom of thought and freedom to express my sexuality to the fullest. We are not owned by our partners.
Now not-so-many months into being a hinge of a vee I could say that this was a good way up. There has been no big drama at all in my practical poly life. My partners were both introduced to poly by me, so they would have totally different stories to tell