What should I do??

I'm a little at loss for how to feel about us moving in together. My boyfriend and I have been together a year and half and we have always lived two hours away from each other. He's 27 and I'm 23. A few months ago he started talking a whole lot more about the future and brought up me moving there. We've had lots of conversations from "you'll do the grocery shopping", to the mushy sexy stuff too. And he's talked to me both drunkenly and sober about how he wants to marry me, buy me a dog, and have 2 kids. Which is great and I get so excited to hear him talk like that. And it's all him, I swear I never bring that stuff up. But Intermittently he starts backing out of living together. On and off again. We'll go shopping for new kitchen counter tops one day and the next he's like "it's a big step". Am I wrong to be so confused? I'm not a mushy person, so I don't normally bring all of that up. I let him do that. I even know he's shopped for engagement rings. Yet he'll tell me on some days that "a year and a half isn't that long" and "it's a really big step" or "I'm just nervous". But I don't understand and I don't know what to do. It's not like he doesn't want to... He talks about it all the time. But it still makes him nervous? What do I do? My feelings are hurt and I'm confused.