Pinkflipflop, I believe your only concern is the fact that you don't know other couples with no kids... there are many of us around! Having children is not "what you do", it's a choice, and one that should be taken with extreme care. In my case, for example, I always knew I did not want children, and I am one of the happiest persons I know... I have a lovely fiancé whom I am marrying next year (he is fine with no kids too), I worked in my dream job for 12 years, I am now retraining just because I love studying different things, we travel, we have lots of hobbies, I volunteer with different organizations, and in the future I plan to volunteer in developing countries... I am not bored for a minute!
And the thing is, I love children! I am the "auntie" who tickles them, rolls on the floor with them, spoils them... but in the end I love giving them back and come back to my nice, quiet house and read a book. I love to hold babies and make faces at them too, but give them back when they cry or when their nappy needs changing :P.
Oh, and we do have a dog, but we don't treat her as a human... she is a dog. If we wanted a little human, we would have one.
Life is what you make of it, and the most important thing is not to choose this or that, but to have the freedom to make that choice. People who regret not having kids are usually the ones who wanted them and could not have them. Very few people who actively choose not to have kids regret it. I am not afraid of being lonely when I am old... why should I? I have time to make friends and spend time with them, I have a partner, I have a family - a sister, cousins, aunties... I have never been lonely and there's no reason why I should be when I am old. The loneliest people in the rest home are actually the ones who have loads of kids, but none of them come to see them.
So my advice is, follow your heart. if you want to have children, have them! If you don't, then don't. But don't do something for fear of regretting it later. You only regret the decisions you did not take. If you choose not to have children, that is a decision you DID take.
Good luck whatever you do!