Just an update. My husband has been trying to avoid the poly talk (subconsciously, I think). I keep cornering him and gently bringing it up. I talked with him last night (for a while), but it helped that I voiced my concerns that I thought he was avoiding it. Also that it wasn't going away, that I was going to be poly either way, and I would rather he had some sort of say in the parameters. After a few hypotheticals, I asked him to choose some person for our life to have a threesome with. He really liked that hypothetical, and I think it opened his mind a little for his opportunities.
Today, after trying to read some Mono help resources, he basically said he didn't need that stuff because he didn't think he would stay mono. If I am poly, he wants to be too! I told him that was great news and might make things easier on him. Awesome!
I know we are in no way out of the woods, or anything close but I can see a glimmer of hope for us and our poly adventure!