Yea - I think you're tangled up a bit in terminology and confused yourself. Your BF it might appear is as confused or more-so than you
Unfortunately the root term "poly" has been grabbed as a shortcut by all sorts of people and in some cases I'm going to say it's been adopted for convenience sake/justification. "Poly" meaning basically "multiple" that's an easy grab.
The "amour" got left off. The loving part. That's not as easy & convenient - ya think ? That means commitment. And lots more.
Let's face it. In the early days, when you are just starting dating etc, just experimenting with your sexuality, there's lots of "poly" happening and not a lot of "amour"
That's perfectly fine. Just don't confuse the reality. At some point some people come face-to-face with a situation where the "poly-amour" jumps up and confronts you. Sex may or may not even be part of it ! But regardless, because of this culture, it's often viewed as a threat. Something hard & difficult. Something to be avoided.
Some of us view it differently. Some chose to embrace & celebrate it. You'll know in your heart what feels "right" when the time comes. But at least you have the advantage of a head start because you've discovered it prior to it happening and slapping you in the head unexpectedly. If you keep asking & learning you'll be better prepared when the time comes.