Your husband wants to "become poly" - I think the first thing to clarify is what that means to him. What exactly is he proposing?
The usual scenario we see for folks considering open/poly for the first time is that the straight husband and the bisexual wife are consider finding a girlfriend for both of them to "add to" their relationship. It's such a common theme that there is a whole meme about it. (Google: Unicorn Hunters).
Is he suggesting that each of you find a person/people to have casual sex with "on the side"? with the understanding that their needs to be rules in place to "protect our marriage"?
I'm reading all about polyamory but I want to hear everyone's story. Please!!
I'm sure that in your reading you have come across the notion that there is no one "right" way to poly - but plenty of wrong ones

. I would second Kevin's suggestion to check out the Life Stories and Blogs portion of the forum, many of us have told the long version of our stories there.
Short version of mine: I have always identified as poly and my husband (then boyfriend) and I have had many discussions about what relationships, love, sex and marriage mean to us over the last 26 years. There were still a few pretty rough patches. I have had a number of female "friends with benfits" through the year, but Dude is my first BOYfriend/serious relationship. The three of us have all lived together for the last 7 years..
I've never thought of it before.
You've never thought about being with someone other than your spouse? How long have you been together? How much dating/sexual experience did you have before you married? What are your thoughts on sexual fidelity, emotional intimacy, love, sex, and marriage? These are good places to start.
We certainly have plenty of fun (and funny) times, however, many people experience a lot of not-so-fun feelings along the way. Poly does have the habit of shining light into all the dark cracks and crevases in a relationship.
