Knew from a young age I didn't want children. Luckily for me DH was ambivalent!
I think people who don't have children by choice generally put a lot more thought into the decision than many people who do have children.
I've seen what having children does to the strongest and most loving relationships - it broke my DSis's marriage, and my lovely SIL has zero respect for her husband following his behaviour after their daughter was born (she's now 17, and I wonder if their marriage will survive her leaving home next year).
I don't find small children and their antics cute. To me, they're just incessant, noisy, unutterably boring.
I hated the thought of years of spending evenings and weekends ferrying children to activities, parties and the like, attending concerts, plays, parent's evenings etc.
You only have to read the threads on here to know how often a vision of having a family rarely matches the reality.
The unremitting struggle of caring and advocating for a child with disabilities, the worry about what will happen to them when you're too old to care for them (have a friend in these circumstances and the anguish she is going through is heartbreaking).
The utter codswallop of the statement 'Children give your life purpose and meaning'. Well, maybe they do for 18 years, but what then - does your life become meaningless when they leave home?
I really like our little life - yes, we do have great holidays, go out for dinner, theatre etc., but it's more the small stuff - cooking dinner together, going to my book group and painting classes. Going for walks without having a small person in tow whinging that they're bored/tired etc.
If we had, for some reason, found ourselves with a child, I'm sure we would have loved it, nurtured it, cared for it etc., but our lives would be very different, and to me, not better.