Thinking of joining the WI or similar in a few years time when the kids have left... any other ideas?
As I'm sure you have noticed, It's not just so easy to find the activities which are for you enjoyable in themselves and which widen your social circle. I was in a similar position a few years ago. My approach was just to join everything I could find.
I looked simply everywhere for opportunities. I read a lot of notice boards, both physical and virtual. The local FaceBook groups were probably the richest source of leads but a notice posted up in the GPs surgery which I happened to visit to collect a letter for someone, has provided ind if the very best leads.
It took purposeful effort and a conscious attempt to rule nothing out and nothing in, and to let go of how quickly things should happen. I kept a list of potential activities and tracking the progress I made which with each. Anytime I felt comfortable doing do, I asked people for suggestions for something new to me. It thought that would be my best chance but nothing ever came of those leads.
The scattergun approach has actually worked quite well. Some things I have joined fizzled out slowly or quickly. Others led on to other worse or better things.
The only thing that I didn't join was the group of dog walkers who very informally tend to walk their dogs at the same time. I did consider it a couple of times when I didn't seem to be getting anywhere.
Of course covid had an impact making some things, the ones like theatres that went virtual easier to access and others more difficult.
Some of those worked out better than others. Some I had to make a bit of effort to extricate myself from. Volunteers prepared to doing anything can be exploited by others to get their own stuff done.
Some opportunities are great but just don't work for me. A few of my favourites have actually changed time slot so they now clash and I have had to choose between them.
If all you really need is some interesting new activities and interests, then start now and just explore every lead that turns up. Give each thing a fair trial. I must admit that some have taken years rather than months to yield really enjoyable things. Others took off very quickly then ground to a halt when the glass instructor moved away.
The other question, which only you can decide, is whether you really want to spend the rest of your life sharing a living space with your husband? How seriously does he control your access to family money? Grumble about you spending or actual control to stop your access?
I've accepted that DH will never share my interests and has no interest in generating any of his own. He is happy with his own company and unlikely now to change. That's fine for me, as he wouldn't ever even think about stopping me and sometimes, very seldom, is even happy to come and say hello to people visiting me.
Only you can decide whether to stay or go. The activities will be necessary (for some people) regardless of your way forward.
All the best.