Etali - good for you and your husband! Altho I have kids and love them very much, I will be the first to say that being a parent is NOT for everyone. And there will always be people out there with unsolicited advice about the wonders of parenthood... well I think I would just excuse myself completely and avoid that person. Perhaps if someone asks if you have children, just succinctly say "no" and then turn it back to them - How about you, do you have any children or grandchildren? Let them gush about their own. Then ask if they are happy with their careers or world travel or reading good books (all the things that are placed aside when you do have kids) and see how much they have to say then!
Also, I think my neighbors who just got married like to respond by saying they're on a "three-year plan" - just want to enjoy their marriage, travel, work, getting an MBA and then in three years they will think about starting a family. Then if asked again, they reiterate, "We're on a three year plan, remember? Ask us then."