Here's my initial feedback: There really is no predicting how things are going to go.
You can say to yourself that you'll only seek out a certain type of person and you wind up with someone else who is completely different than you anticipated or hoped for.
That being said, it's still perfectly valid to pursue the kinds of people and situations you are comfortable with, until you get your land legs, so to speak. I know I don't necessarily seek out people who are immersed in poly or part of the poly community where I live, simply because I'm not that crazy about the men I've met there. Slim pickins'. What I am discovering is that there are plenty of "non-poly" people who have lived polyamorously and are open to it but just never heard of the word. The label isn't important, anyway. In fact, I've had my online dating profile up since last Fall, and have only now added the word "polyamorous" to it.
I also was really intimidated at first (I'm new to this, since this past October) by the idea of being involved with someone who is married. It isn't until now that I am embarking on a relationship with a married poly guy whose wife has a lover and has welcomed me in emails!! I wasn't seeking that out, and was perfectly content to continue looking for single guys. This is such a wild ride for me, I don't think I could have been comfortable in this dynamic before, now that I have experienced being involved with more than one guy after my separation. Baby steps are fine -- but leave room for the unexpected to happen!
And just a caution for you: don't expect all things to always be equal between your and your husband. You are two individuals with separate needs and energies. One of you might have a potential opportunity wa-a-ay before the other one. I would say, that could be a very good thing that would help you both get used to the idea of one of you having a second relationship before the other does. That euphoria that polyfolk call NRE hitting two of you at once might be more difficult to manage. But maybe you both can handle it - the thing is, like I said earlier... there's no predicting!
Set goals, allow for preferences, but know that you both might have to toss it all up in the air and go with the flow of what life brings you at some point, and surrender to some surprises along the way.
Good luck and welcome!