I'm (40) childfree by choice and have been with DH (43) for 20 years.
Apart from a couple of blips, lasting a few weeks here and there in our early 30s, we've never wanted kids.
I love the small freedoms of not having children. Going to the gym or for a run multiple times a week, eating really well, having a lie in at the weekend, deciding on a Sunday at 12.50pm that we want to go out for lunch and leaving the house 10 minutes later, taking the dog for a long slow stroll in the sunshine after work.
I also love that DH and I can invest in our relationship. A lot of friends with kids seem like ships that pass in the night, although they do make it work.
I never miss having kids or wish I could trade with anyone. Even times like Christmas, which for most people are all about kids, I love our quiet childfree Christmases.
Unfortunately, we both work full time, so it's not a life totally free from ties and responsibility!
I'm someone who can keep myself busy endlessly with the gym, dog walks, social clubs and so on, so I'm not concerned about potentially being on my own one day. We live centrally in a market town with loads of amenities on our doorstep. Meanwhile, my PIL live out in the sticks several hours from DH and his sister and are in chronic health, and see their kids (who both work full time) for a few hours a few times a year, so being parents doesn't mean they are regularly in the company of their children.