First, HAPPY ANNIVERSERY!
I think most of us have an addiction of some sort. Some kind of void we need to fill. Whether speed, handling, or not having the car we wanted as teenagers.
The hardest thing to me about relationships is understanding your partners needs and where they are at in life. Let's face it, I'm going on 16 years of marriage and would have given up EVERYTHING to be with my wife and just about did because she was more important. Now 16 years have gone by and I want what I had before I was married!
Nothing really wrong with it, I don't want a divorce or want to sleep around, I just have hobbie(s) that help fill that void, whatever it may be.
For my relationship I find it easiest to sit down and tell her what, why and how I want to attain buying whatever, and I'm honest. For the most part, it works out very well.
An old friend gave me some advice, if you both don't agree on the topic, don't do it, but remember, if she really wants something and you don't agree, she has to follow the same rule.
Funny, one of the best compliments my wife ever gave to me was how much money we saved by me working on our own cars. Only relates here if it is about money. Use it as an angle if it helps.
Is the bottom line money or safety, both? Likely, with a daughter, she is thinking of your safety and protecting her daughters father and the household provider. Nothing wrong with this, but it is where she is at in Life and it is likely the most important need on her list. (Yep, It's weird!)
She's probably thinking, what if he was killed, I'd have to date, get a better job, whatever.
Now, no offense, I've seen this many times, she could just be a complete control freek. Then you're screwed!