I always trust inexplicable feelings. You should probably talk to him and ask him to go slow.
I don't really see relationships as a scoreboard where everyone has "equal freedom" to pursue things. It may sound hypocritical, but in my view, every person is different and the challenges and strengths that come with it are different and what may be fine for one person to pull off, could be a problem for another.
I am just giving an example of this "inequality"
I was the one to insist that my relationship with Spexy be explicitly NOT one that promises monogamy. Neither of us were interested or inclined to pursue anyone else, so we didn't really discuss this beyond accepting that people feel what they feel and as long as we are committed to each other, we will not "own" sole rights to the other.
A year and a half down the road, Spexy got into an affair (cheating) out of the blue. Technically, we had not put a definition to our non-monogamy. But the way he handled it between the two of us didn't work and he pulled the plug (I was very close to an ultimatum if he hadn't). Even ending it was very messy.
I didn't have any intentions of finding another partner, and didn't bother just because Spexy had opened the relationship.
On the other hand, once the dust died down on his relationship, Spexy is convinced that at least at the moment he definitely doesn't have the skills to handle two relationships. I had concluded that in a moment of fury over how I was treated earlier and "grounded" him to monogamy unless he negotiated explicit exceptions (which sort of brings us to consensual poly, actually).
He took it a step forward and has chosen to remain monogamous. He is happy with me and while he doesn't believe that monogamy is inherently virtuous or anything, he believes it is practical for his skill level with relationships. I agree.
I have not committed myself to monogamy at all. I still am not looking for anyone, but if I choose to, I may.
At no point have we been "equally" non-monogamous. Sometimes the difference is from ill-advised action, sometimes from choice tailored to a specific person.
So I think, there is no rule that says that just because you are poly, you "have to" be ok with your husband being poly too. He is a different person. Will he make a good hinge? Will you be able to handle his being poly? What are the challenges? What are your needs to feel okay with it....? I think you should speak with him and find a safe space in which you can proceed. It may sound hypocritical, but IMO, it is a life hack - may not be "perfect" in terms of everyone being allowed on basis of one standard, etc but in my view will be emotionally safer and more likely to succeed if you pay special attention to each person.