I'm another 40-something, married without kids by choice. I think it's important for people making this huge decision to know that there are happy individuals and couples on both sides of the fence. We hear a lot about happy parents, and that's great, but there are also happy non-parents. It's just hard to say much about it, even when asked, because people can end up thinking you're just a cold selfish child-hater.
Maybe I would have enjoyed the parenting life, but I enjoy this one, so I have no regrets. I think there are many paths to a happy, fulfilling life. I agree that there are a lot of things that can go wrong in the world of children and parenting, but for us it really just came down to the fact that it wasn't a "hell yes," for either of us. We are not people who light up around babies or kids. (Same with my one sibling, so our parents got screwed on the grandparent front!) All my life, I've known several couples who didn't have children, and they've always seemed just as happy as those with children, so it wasn't a difficult decision for me.
I don't see dogs as being all that similar to kids, and I recoil in horror at the phrase "fur babies," but I do spend a ton of time with my dogs and love them to bits. Maybe my parenting gene was replaced by a "dog nut" gene.