This sounds tough.
Can I ask - you have been on the area for about 10 years (I presume) is there a reason you didn’t manage to make friends and build some support system?
Moving 150+ miles away has worked for the poster above. But in your case - with kids settled at school and the community - you can’t just move your kids unless your H agrees to it.
You need to divorce first and negotiate a child sharing arrangement. If your H actually goes for 50/50 time split - then your ability to move anywhere far would be limited. And for a good reason. Kids need stability. Especially as they are dealing with massive changes that are the divorce.
But even if you can’t change everything in one go, you can still start making changes.
If you are this unhappy in the relationship - divorce. And see if that makes you happier.
You can date and see if there are those new and exciting partners to have fun with out there for you.
Your post reads like a combination of genuine unhappiness and depression. When we feel this way - we tend to look for greener grass elsewhere. Or dream of escaping. You want a different life, in a new city with a new partner. This is very typical.
Before my divorce I was unhappy for a long time. Fantasies about another life somewhere else is very familiar. So, with a bit of benefit of foresight - I’d say - if you have decided you are done with the relationship - plan out your path. Do that before you inform your H.
Figure out your financials, talk to a solicitor to see what is possible/likely in your situation.
The poster above who says he just moved away three months ago, with zero plans or income and feels so much better now - left without his kids.
If this is something you can do - you could go try out living in a new place on your own. Personally, I couldn’t leave my kids for months, no matter how unhappy I were.
And in addition - it’d weaken your case if you and your H went to court over child arrangements.
To summarise - if your relationship has reached a point where you are so desperately unhappy after trying to fix it - i do believe divorce is the best way.
It’s going to take time and it’s a horrible process - so plan and prepare.
As attractive a dream of running away to a new life is - it may not be realistic. But the changes are still possible. And you can make your life better.