single income household with two kiddos
Well on your side with only one car payment, teach her to drive it or sell/trade it.
My wife wants a new (used) car as well, I tell her the bigger the stack the nicer your car will be, shes OK with it and completely understands. We have three cars and all paid for, the house is also paid for. To quote James Brown.. IT FEELS GOOD!!
Side note> If your thinking about a newer car (under 30K miles) the money guys are all saying that three years ago leases went crazy and cars are now coming off those leases in the thousands. Used car prices are already seeing a lot of downward pressure.