Partner got cold feet, keeps making excuses.

So, my partner and I have been together for five years. He always talked about wanting kids and wanting to be a dad and talking about wanting to buy things a head of time like stocking up on diapers and the like. We decided to start trying in March, but our attempt was unsuccessful. We chalked it up to the fact that I had just gotten off birth control and decided to start trying again in September. Well, now he's saying he wants to wait and comes up with new excuses constantly. One day it'll be that he wants to move first, the next it'll be because he wants to buy a new couch because God forbid we can't both be completely sprawled out on the couch at the same time (seriously, it's the dumbest thing I've ever heard, we may as well put a bed in the living room), and then it'll be that he "never agreed" to these plans in the first place (spoiler, he has. A bunch of times). He's driving me up a wall because this was something we actually talked about and agreed on and are making actual life plans and life changes around and he's not exactly contributing much. Has anyone else ever dealt with a partner who kept flip flopping? How do I handle this without seeming like I'm attacking him? I want kids, and I want them with him, but I also don't want to end up never actually having a baby because he kept finding reasons to put it off.