I don't understand what makes you think that if you and he were to both buy a new car, it would cause you both to go on some wild spending spree. I mean, are you saying that you know yourself, and him, well enough to know that neither of you has any self control when it comes to money? If this is not the case, and you haven't been "wild spenders" in the past, why would you suddenly start now - especially now that you are going to have an addition to the family which involves a lot of additional financial output?
From what you say, your husband's reasoning about why he wants you to have the new car, is pretty sound. He wants you to be safe, particularly as you will obviously be transporting your child a good bit. LOL if your hubby is making 94K in his job, sounds to me like y'all would have to go on one awwwwfully big spending binge to get into debt, and if the danger of a spending addiction existed in either, or both of you, I suspect you would have been splurging already, with or without buying a car.
Why don't ya just sit down with him and do the old compromise thing. Tell him what your fears are, and explain that you are wanting to be sure that the two of you are going to be completely on the same page when it comes to the family's financial priorities. Babies are very high maintenance, and you're going to be budgeting for significant extra expenses from hereon. Plus, if you are like most young couples, you've probably got mortgage payments on your home and, if you both go ahead and update your wheels, ya got two lots of car payments to factor into your monthly outgoings. With his kind of earning power, that shouldn't be a problem, but, explain to him that you have a very big thing about staying on solid financial ground, and you'd feel a lot better if you can have his reassurance that he wont be wanting to step outside the boundaries of "sensible spending". Even people making a high income can easily get into debt if they are lured into living beyond their true means, but, again, if your husband has not shown any signs of being like that up till now, it's hard to understand why you would think there was a danger of it just by buying a couple of new vehicles. You're going to have to do it sooner or later anyway, and his safety argument is, as I said, reasonable.