My first thought is that maybe he REALLY doesn't want to have more kids right now. He knows you do, and he knows how babies are made, so.... well, he's avoiding it. It's also possible he's one of those people who enjoys the thrill of the chase, and now that you're married, well it's not that exciting to him anymore. Unfortunately, the only way to find out either of these things is if he is willing to tell you, and that will only happen if he's actually AWARE of them. Sometimes people develop these kinds of adaptive behaviors and aren't even aware of why they are avoiding sex.
I'm sure some of the other posters will chime in with more help and suggestions in time. I'm so sorry you are going through this, but you should know that it is fairly common. I've seen this type of thing a lot of times in my years on this board.