You definitely need to agree on how you'll spend your money before you marry and begin a family. You may shift your thinking after the fact, but you need to begin together on solid ground. Even if it causes friction between you, do not go ahead with any plans before you reach an agreement.
You said food is a problem. Start with that. If you can attack and solve that one problem, she'll see a difference in your budget, and she'll be open to hearing your suggestions for other topics. On the other hand, if you try to do too many things at once, you'll likely meet more resistance.
Having said that, I think you may be expecting too much on the meals-out thing. Her schedule is something of a nightmare for food preparation. I think you can improve the problem, but I wouldn't expect a person with her schedule to find a way to completely switch over to a nearly 100% home-cooked from-scratch lifestyle. Admit to yourself that while home-cooked meals all the time are the ideal, the circumstances of your lifestyle may prevent that ideal from being possible in your situation.
I can, however, see a number of ways you might improve the situation, and that's what might work best.
- The biggest problem is that she comes home tired and exhausted from several days of work /time zone changes. You make yourself responsible for having a lovely glad-you're-home meal waiting when she arrives. Tablecloth. Real dishes. Wine. Reluctant spouses are often more willing to make changes when they see that you are doing your part.
- You make yourself responsible for keeping the pantry stocked so that she can cook once she arrives home. Ask her to email you with a shopping list.
- Use a grocery delivery system. Two of our local grocery stores have this, and a friend of mine with two toddlers said it is worth the $4.95 fee to pull her car up to the front door and have a stock boy run out with her prepared bags. If your girl travels with a tablet or computer, she could use layover time to place her order /pay for the groceries with a credit card.
- Agree that her first night's dinner will be a meal out. Always. Then once she's rested, comfortably returned home . . . THEN you'll launch into thrifty homemade meals.
- Research foods that can be prepared with only shelf-stable goods (look into food storage recipes from the LDS church). These aren't as healthy or as varied as a usual diet, but if you could have some meals ready on the shelf, you wouldn't find yourself forced to go out.
- When you cook something, double or triple it and freeze the extra meals (sometimes called batch cooking -- I love it myself because, for example, a big pot of homemade soup is the same work as a little pot, but you can eat from it much longer). Lasagna, chili, and enchiladas, for example, are great freezer meals. This'll allow her some quick and easy things to cook. Since they'll need to defrost, they'll not help for your first-meal home, but cutting down on the work would be a step in the right direction.
- Part of the problem may be that she's not willing to invest in food, knowing that it'll spoil while she's away. If this is indeed a problem, consider buying the smallest portions, even if they're not the best value. And consider freezing what you can freeze (for example, last night I had 1/2 gallon of buttermilk, which I use only for frying chicken and making cornbread -- I used one portion, and I froze the rest in 1/4 cup portions).
- Finally, can she cook well? If she's not a good cook, her lack of knowledge or insecurity about her abilities might be hidden by complaints about time and convenience. If that's so, perhaps a gift of a couple simple cookbooks could put her on the right track (many new books contain pictures so you know you're doing the right thing). And if you cook together and show an interest in what she's cooking, you may find her abilities will grow quickly.