Thanks for sharing your story.
One thing that comes up for me in reading what you wrote is a sense that your husband may be pushing you a bit, even possibly manipulating. But you need to take your own time to feel and think ... and thinkfeel ... through all of this polyamory stuff, about the social conditioning you mentioned, etc. You might consider telling him that you may move through your self-inquiry process on this FASTER if he'd take a less pushy approach to "encouragement" (my word, in quotes because its uncertain how encouraging pushing really can be).
No one should be forced into polyamory, nor pushed.
Meanwhile, you and your husband can explore being spontanious with one another, deepening your relationship, building a bond that is strong enough to work which ever path the two of you take in the future.
Just my two cents.