I really want another baby...

But my husband is being frustrating about it... We both agreed that we want 3, maybe 4, kids. We already have a son, who is almost 2. I'm ready to start trying for another baby, but my husband isn't. So we compromised and agreed we would start trying in December. But now he's saying he isn't sure he wants to start then, that maybe he wants to start trying sometime in 2018 instead, but he isnt sure so I should just keep December in mind to start trying for now. That we would see how we feel when December rolls around and decide then if we are ready to start trying. I was impatient, but okay with starting in December, because at least then there was a set end in sight for the waiting. But now that he isn't sure, I don't know how to feel. I want another baby so badly. I want my husband to be 100% percent on board with the decision to start trying to another baby. I want him to be excited and want to start going for baby #2. But I can't stand not knowing when he will finally be okay with it. Anyone ever been in a similar situation? Tips on how to deal with the baby fever (and the mid depression that comes with it) in the meantime?

Sorry its so long, but I needed to vent...