That's exactly right. It's interesting that we are often accused of not believing in the value of repentance since we see God as being all-sovereign. Yet, it is the Reformed view that repentance is critical both in the positive sense, and also to avoid something that is very very real.
The failure of humanity to repent ratifies his sin nature for all eternity, which he will still have as his nature when the wicked are resurrected to eternal damnation.
Now, I ask that this be considered concerning the "burning" aspect of hellfire.
For all eternity the desire for the sins which were the driving force of the affections of the wicked will still be present with the wicked, however, they will not have the circumstance to fulfill them, not even once, for all eternity.
Would that be like being in "fire"?
I think so.