Being poly means so many different things to so many different people. For some, it means there is a 3rd person with whom you are both engaged in a relationship. For others, only 1 of you is engaged in another relationship.
At my house, we are both free to seek relationships with other people. We also choose not to "share", meaning that we don't pursue the same person. For us, it gets too hard when one of us starts having difficulty in that relationship but the other person is still fine with it.
I can honestly say, and my husband would agree, that we are closer now than we ever were before because now we know how important it is to be honest and open, in a real gut-check kind of way, with one another. If ever there was a secret to success (20+ years married), for us, that's it.
That's not to say any of this is easy. It's complicated. It's messy. It's emotional. It's gratifying. It satisfies needs for both of us that the other is not able to fulfill. And, most of the time, it's fun.
You both say you are talking. Good. No, GREAT! Keep it up. Be prepared for your attitudes to morph over time, not in the next week or two. It took us years to find our comfort level. If you both care about one another, respect one another, and really want the other person to be happy, I think you will have a great starting point for your discussions.
Best of luck to you both!