Wife and I are early 30s and decided not to have children. That may change but for right now that is how we feel. I am apathetic on having kids and her view is that life is misery so why bring a life into the world to experience that misery. I don't understand the rationale as she has a very comfortable (economically speaking) life but result is positive for me.
As a result, our lifestyle means that we can live in multiple cities which we do and tend to plan every event / travel last minute. It has been great and now that we have a dog it has reinforced our desire to not have a kid. It is too much responsibility.
Her view which I believe we could afford is that we would only have a child if we had a nanny 100% of the time. It comes down to neither of us feel a strong desire to have kids and both agreed before marriage that we would only have them if we both REALLY wanted it due to cost and time commitment.