Butting heads

I'm a FTM and my partner and I keep butting heads over things. He makes me feel like I'm being ridiculous and over the top when I'm just trying to do what I feel is best for our little one. For example, I say that we need to go in separate cars when we're going somewhere with baby, dog, and a heavy pushchair, as I'm worried about the base of the pushchair hurting one of them if we got into a collision. And going to a party at his parents' house with lots of very distant family and their friends in attendance, he acted like I was crazy for not wanting to put her down asleep and just leave her alone where anyone could get to her. I just love her so much, and I'm being made to feel crazy for wanting to keep her as safe as possible. He keeps saying that some people wouldn't have the luxury of two cars and would have to take the risk, and I know that's true, but why risk if we have another choice?? She's four months old and I'm already tired of fighting the person I thought would be on my side to get the best for her. I'm tired of being made to feel crazy. I don't know what to do.