The issue isn't retiring to Florida, per se.
The issue isn't even really retiring, right?
It's moving. And to me, unless there is a truly pressing reason to go such as a vital job change or an illness that requires relocation -- if one spouse says a strong "no" backed up with a ton of reasons, while the other says "yes" backed only by "I like the climate better" with zero research behind any other aspect of a move.... The "no" wins, at least until both partners have spent a HUGE amount of time and energy doing some very serious research that includes spending substantial amounts of time actually living in (not just vacationing in) the destination spot.
I am confused about why the careers of your adult children are such a huge factor here; they are all out of the house -- or are they? If they live with you, it's past time to get them moved out except perhaps the one who has you as his base while he finishes college. And their moving out (if indeed they live with you, still not clear on that) should happen ASAP even if you and your husband never leave your own home at all! However, I would wager that the real issue with your adult kids is that you just want to remain geographically close to them, and as long as you are not doing it to support them financially or provide a roof for them - that is totally a fine reason to stay in an area. If you and they are close, there's nothing wrong with wanting to stay where you can go to your daughter's modeling shows or music gigs, or where you can be around as your kids get married, have kids, etc. But let that, and not "they need us here for career reasons," or worse, they need us to finance everything, be why you stay. I'm not sure why you write that "they don't want to move and disrupt so many things they've worked so hard for" because why would three adults all move because mom and dad move, unless you pay for everything they do--?
And if you like your job, why should you leave it? Does your husband have some pressing reason he wants to leave his job or hates his job? Is that really what drives his yen to retire, and Florida just sounds good and warm to him? That does not mean your own career should be dumped. If his own job is the problem, he needs to work on THAT problem, and not just focus on escaping it.
He really needs to examine why he's on this hobby horse right now. Midlife crisis? Job issues that make him want to give up and pine to be retired and boss of his own time?
Have you spent any time in Florida other than maybe vacations? My friend's parents (from NYC) retired there based just on a few vacations. They moved back to NY in a year. They had never actually spent more than two weeks at time there; had never really looked at properties, checked out what there was there to interest them, done day to day things every day for a longer time. They just had heard that "everyone from the north should retire to Florida" and went with that, but they were dyed-in-the-wool New Yorkers and found it wasn't a cultural fit for them. Not dissing Florida here, but saying that ANYwhere you retire, you need to do some serious time there first. I wrote an article some years ago about that very topic (used to be a reporter) and all the advice from aging experts, career experts, relocation experts was that people need to do far more due diligence investigation of a potential retirement location than they actually do. Has your husband thought through what would happen if you sell your home then regret a move (to Florida or anywhere) and can't get back your home or even a home remotely in the same area or in any price range you can afford?
You and your husband need to have a very serious sit-down. You need to be cool and not get all emotional about "I want to be here for grandbabies!" and so on. But you do need to get your opinions out there very clearly and talk about what isn't negotiable for you, and ask what HE most wants - and why; there may be depression or just plain job frustration behind this. If he has real and serious issues with the climate he needs to see a doctor about that; there are medical conditions such as seasonal affective disorder that can be treated. Again, as with job issues -- he needs to treat the actual problems he's having, not run away from them in the name of retirement.
You can try what my friends did --they got a high-quality RV and traveled the US when they retired but kept their base where the adult kids were and returned there for longer stints when the kids had grandkids. It's not for everyone but it worked for them well - they got the wanderlust out of their systems each year, and could spend long periods in warm places, but also had a permanent base near the adult children.