With just this information, I don't see why you would block the purchase. You've crossed the finish line, and as far as hobbies go, that's not the worst expense. You couldn't travel the world for that, and could easily spend that much on a woodworking shop. And it wouldn't be that much of a sports car. (As examples)
But to dig a little further:
How much experience does he have with simulators? Does he *think* he would enjoy it, or *know* that he would enjoy It?
I assume, given the timing, that you are in a northern state, and...winter is coming. Does your DH play regular golf? Has he had the opportunity much since Covid hit? I could see a mental space, much like many home improvements in the past 18 months, where this is a "Covid proof" way to golf. And of course, It's a cheaper option, over time, than traveling in the winter to play golf in a warmer place.
(Edit: I see you have just answered the frequency question)
I do think It's a reasonable request to look at used options. What's the price difference? If his hangup on that is condition / risk of problems, does the company sell refurbished / factory warrantied used ones? You may not end up getting used after all, but at least knowing the market is useful information. If he has made good choices through your marriage, then as
@Malcat said, I think you need to trust his informed decision.
Another potential compromise, to check if it might be a fad: is there some place with a simulator that he could go to? Not as convenient as having one at home, but maybe get him a membership with a simulator so he can try it this winter. And if he still really likes it, look at used prices in the Spring, which I imagine would be the off season since the weather would be warming up.
The other thing given the price tag: is it available for a medium-term rental? It might be relatively expensive, so he might have put off the idea. But if you think It's worth a $1,000 bet to make sure that he will really enjoy the $10,000 purchase, then tell him you would be OK to rent one first, again to make an informed decision.
The other caution is: is this the only aspect of the purchase? Where would this go in your house? That place has high enough ceilings for a golf swing? And what about errant balls? There could be some good dings in drywall, or ricochet off of concrete. I'm minfull of
@iris lily 's story, that the car then needed a garage. This doesn't change the facts that you can afford it, and it seems to be his one big dream. But in making his decision, It's fair to make sure that *he* has added up all the costs, and still wants it--again, an informed decision.