OP my situation is different. You probs ky think I was lucky. By 29 I had been married 9 years and had 2 kids.
But my husband was abusive (though I didnt realise until my early 30s) he isolated me from everyone and cause me huge amounts of self esteem issues. We all so worked together in our own business. I knew no one except my husband.
Despite having the family etc. I was desperately lonely. When I realised I was being abused I made a plan to leave which included me getting employed work. I knew I needed to make more effort with friends etc.
Through that job I met my 2 best friends. Someone 10 Years younger and someone 25 years older. The younger had young kids. The older one had adult kids.
Because we all wanted to be friends we made it work. 2 of us would have rush home. But we could also make time for the older one and arrange nights out. Anyway 18 months later my, now, exh husband attacked me and I fled with my kids. I got a divorce and a house.
I remained friends with the 2 other women. But they didnt understand the crushing loneliness at home every evening. Worrying about visiting rhen incase they were having lovely nights in with their family or partner. They tried to understand but they couldnt. Then the bastarf ec took me to court and got access to the kids. So often I was alone in my house. Which was nice at first. But day in and day out it wasnt. I was afraid I'd being the 5th wheel to them.
But we all still made the effort. When my kids werent here we would arrange nights out. If they were, days out.
During this period, despite having friends I felt desperately lonely. Because I went home alone.
Anyway, the younger ones brother has got a divorce and was moving back to the area. 3 years later we are together and happy. For the first time, ever. I dint feel lonely. I had a poor upbringing. Felt lonely them too.
These women, gave me the strength and support to leave my marriage. They didnt understand the crushing loneliness. But they were good friends. Especially the younger one.
I put lots of effort into those relationships. And it was worth doing. There are there for me and I am there for them. I have got my son son up in the middle of the night and gone round because one of her kids has needed to go to hospital. But my son to bed there and driven my friend and child.
They have turned up here in the middle of the night. The younger one is like my sister. It's the best friendship I have ever had. Hee brother my dp, knows that when it comes to adult relationships, she is the person I am closest too. The older one is still a good friend. But retired now and off travelling the world.
My point is that age doesnt make a difference (you mentioned everyone being retired at a club you went to) in friendships. You cab have evenings out with those who have kids. But you all have to put effort into friendships. Work friendships done have to wane. We dont work together now. But I make the effort to message them, go see them, even call if I feel a bit down.
I know my life is different to yours. All my twenties I knew my marriage was a bit shit, was always lonely, always had been. The power was in me to change it. Just like it is in you.
Also I live on the edge of a mining town in Yorkshire. You dont have to live in london to go for dinner after work. Women with families do still go out maybe not every might. But they still want to go for dinner etc.
Until you accept that you can change it if you want. But it will be hard, but you can change it. Nothing will change.