That was our experience too, we found it very hard to 'break' into any social circles, they seemed quite closed as friendly as we were, and still are. Maybe in time it changes if you live there for decades, or if you are married to a local man perhaps? But for us it wasn't easy. They were cordial but distant, we had a handful of friends and the odd supper here and there, it was socially very limited.
Yes you are right every village, town and city in the UK will have a whole host of activities, clubs, workshops and gatherings of every kind. Every pub is pretty much a welcoming place wherever you are from, and there is a fluid social life that you describe very well, and everyone is welcome. So much so that I have to hide when walking in my village, otherwise I am roped into Tuesday's supper club or running the blinking book club, or asked to pop in for a coffee that takes up all morning.
I could not find any of these things in our village or surrounding areas in France. Most of the women I knew would cook in the evenings at home, and sometimes go out for dinner at the weekend with their dh. Older men would sit in the bar, or outside with each other, the odd game of boules was the highlight. Going to restaurants was our only option, and we quickly tired of it.
We liked it initially because the region was peaceful and quiet, but once there it was too much. Even for my dh who is not a social butterfly by any stretch. It was much more lively and interesting in Paris, and also in Monaco, with more options, but if your dp won't move there - then that doesn't really help you.
I just wanted to say I really get it, and I understand why you long for a bigger life in all ways, with more colour, friendships and interest because that is how we felt too.
' Living the dream' for us actually equalled a life that was incredibly boring and isolating.
It got worse as time wore on, and the winters there were the worst. Maybe it was the lack of good heating in our house, the damp and all of the windows everywhere always shuttered up. In the winter here you have the glow of houses, windows, lights and activity - the french villages were like ghost towns and howling winds in the winter made me feel so lonely. Maybe it was just where we were, and it is better elsewhere.
Don't settle for a life you don't fully love and feel connected to.