Again its simply understanding what you want. If you could only answer that with a NO...then maybe you need to reflect the why you are poly part.
And really, if its JUST a sex thing for you, you are a swinger...nothing wrong with that...but lets call a spade a spade
(ps you can be a swinger AND poly...
Take ownership of what poly means to you...and create your own definition, but allow it room to evolve. In my relationship my wife and I are open...bordering on swingers but not nearly that random...we are also poly because we know we can love other people. I am not walking around looking for everyone to love...I am also not walking around humping everyones leg.
Something you can just say, and bam...proof that i'm not some irresponsible whore. This is what it is, what is why it's awesome.
Ask her to read this site...have her read xeromags musings on poly...have her read the ethical slut AND opening up. Hopefully, since you are in this, she will take an interest and want to know more. With all 4 tools she might have a better grasp of what poly is and isn't.