I've been in a number of region and nationwide nerd culture organizations, LARP clubs, subcultures, et cetera, all of whom accept and work to help people that live alternative lifestyles. I've been a LGBT supporter for decades, and generally have a strong liberal mindset when it comes to social issues.
As a result, it wasn't so much one moment that the concept of Polyamory really came to me - I think the first time I ever heard the term was some MTV special back when I was in high school, but I didn't give it much serious thought. Later on after my first few years out of college, I got to a weird point in my relationships and started realizing that I was in love with several people, even though I was only "with" one at a time. So, research began and it started dawning on me that this might just be my thing.