Hi Boz! So, I feel your pain, having married a spendypants who eats in restaurants with friends every weekday, and who insists on buying Diet Pepsi from the machine at work even when I stocked the fridge with grocery store bottles he could take in.
So, first, read the awesome "how to convert your SO" thread.
Second, it sounds like you guys keep most of your money separate, except for a joint savings? I think separate accounts means that as long as she is covering her share, you don't get any say in what she does with the rest. But even if you were completely joint, there's only so much you can do. One thing DH and I did was set up a single joint account for everything, and then each of us got separate allowances out of that (I called it -- privately -- his "stupid money," because he could go buy stupid unnecessary shit with it, and I had to shut up as long as he stayed within his allowance. Kept me from becoming a total harpy). You guys might be able to work out some compromise along those lines -- something that lets her feel the freedom of those stupid purchases she likes to make, without messing with the overall plan. But if you keep your finances separate and she is paying those loans out of her money, there's not much you can say or do about it. Except for the slow art of gentle persuasion. Which brings me to . . .
. . . two big-picture things you can do to help bring her around over time:
1. Start talking about dreams, plans, goals, etc. "Retirement" is very vague and far-off to some people. You guys need to figure out what you are working towards -- not things you are running away from, not vague "wouldn't it be great," but dreams you can't achieve while in debt and working for a living. She has to want the goal more than she wants McDonald's. (Note: I find the liberal application of wine, a back porch, and a lovely summer's evening helps these conversations immensely). This, of course, is a slow, multi-year process, because she is not going to believe it is possible. So in the meantime . . .
2. . . . You lead by example and entice her away. Of course McDonald's is tempting (I personally go apeshit over a Big Mac), but is it more tempting than a delicious gourmet meal prepared by her loving husband? Come up with things to do on the weekend that don't cost money; take the lead in grocery shopping and menu planning; figure out how to insource as much of what she wants to outsource as you can, and show her what a great life you guys have and how much money you are saving!
Note: I realize you can't do it all -- honestly, this is where my own efforts bogged down, because we have two jobs and kids, so I menu plan and cook, but I am damned if I am going to spend my limited free time scrubbing toilets. But part of this exercise is figuring out how important FIRE is to you, and how much you are/are not willing to do for it. I bet, over time, if you are patient and focus on what you can do vs. improving her, she will see your efforts and work to meet you halfway. And you will probably have to compromise, too, and meet her partway as well.
This may or may not work, and it's a long road. But it's not like there's any better or faster way to convince her anyway. So just give it your best shot and keep loving your family and socking away the money yourself. Good luck!
