Hello, my situation is slightly different to yours, in that we already had two DDs. However, we desperately wanted a third - the yearning was as great as it was for our first. When we started trying for DC3 it took ten months, followed by a mc at 3 months. We tried again for 5 months, got pregnant and then mc again at 3 months. We started trying again and I was getting to the stage where I thought enough was enough and, despite the longing, we would have to give up. Lo and behold, after 10 months of trying I got pregnant again. I'm now 25 weeks and all seems well.
I don't know whether this helps or not. All I can say is that you are most definitely not alone in feeling as though it may never happen. For some people, of course, it doesn't but for the vast majority it does eventually. I had one friend who tried for her first for over a year and then got pregnant the first month of trying with her second.
Keep going. You will obsess, it's impossible not to, but just make sure you have lots of sex (don't stop too early in your cycle - I think that's what made it harder for us as it turned out I ovulated later than I thought, despite me 'tracking' my ovulation) and look after each other. If sex feels like a chore then don't force it. I feel for you. It's taken us 3 years to get to this stage and I know how all-consuming it can be.
FWIW, when I had both mcs, I didn't think of it as my body failing me. I thought that, although it was dreadfully sad, my body was doing exactly what it was meant to by not continuing with a pregnancy that was non-viable. Our bodies are clever.
I wish you all the luck in the world. I can't say you'll get there, because who knows, but the chances are good.
Take care.