Poly is about honesty right? So if you're honest with each other and you know at some point the other person might be dating someone else....how is that not poly? And why does it have to go beyond that?
I wouldn't feel the need to introduce someone to my DH if we weren't married. I'd tell him I've been interesting in this person and we're going to a movie but before we were married and before we lived together? Nah. My life is my life. There's a difference between honesty and full disclosure I think. Not a bad difference just a difference.