I first heard 'Polyamory' as a label in 2001. My husband and I were 'bad' swingers, because we had 2 couples we were exclusive with, and did things outside of the bedroom. Our kids hung out, we had them around our families, friends, 'feelings' were involved, etc.
I, like Redpepper, always refered to myself as 'non monogamous',...Then someone in a swingers chatroom called me a polygamist, and someone else corrected them, and said I was polyamorous.
I tend to shy away from labels, and stayed with the 'non monogamous' until this past year.
I do know when I was first 'labeled' I looked it up, and found information and writings, from the early 90`s and onward. I didn`t pay to much attention at the time though. Wish I had.