Not sure which thread you're looking at, so copied from the other one:
Former picky eater (yet now completely reformed) here. I did a few different things to get a taste for vegetables and different ethnic foods. I started by getting meaty oven bake pizzas (good ones) and putting things like bell peppers on them. After awhile, probably between 5-10 pizzas later, I started to miss the bell peppers if they weren't there. I figured out that there are other pleasant flavors than "savory" and "sweet." Fried rice is another good savory dish with vegetables in it where you can gradually up the veggie content as the person gets more used to it and crave the "freshness" of veggies to lighten it up. After I got to where I liked vegetables, I went with coworkers once a week to an ethnic place I'd never been. I'd get the most "mainstream" dish there, and at least try everything. I didn't like it all, but did end up liking most of it.
I think getting involved in cooking helped me a lot too. Jamie Oliver got me interested in what I was eating, and showed how "proper" meals should be cooked. I don't do too much of his stuff anymore, but he's pretty inspirational (his TED talk is really good as well) and fun to watch. The difference from what I thought a salad was (flavorless lettuce, a huge hunk of bland tomato, and a few 1/2" thick slices of cucumber with some shitty bottled dressing on the side) vs what a salad can actually be (mixes of greens, dried cranberries, toasted walnuts, with a honey vinaigrette tossed evenly over the salad. Also love a good caesar.) is mindblowing. I remember after having one of those real salads I thought "THIS is why people eat salads, it makes sense now, this is actually good!" Depending on where you live, good quality restaurant food may not be around. Frying food is easy and cheap. Properly grilling fish or vegetables, or making a good quality salad is a bit harder to train someone making minimum wage to do. Going to a relatively pricey place occasionally is probably worth it to get her to try new things, then you can learn how to make them at home. I go with my girlfriend to a restaurant called "North Italia" a few times a year. It's pricey (~$20 or so per person if you split a salad), but we get a new salad whenever we can and then try to reverse engineer it to make at home. I actually just had a try at making ciabatta since they always bring it out as an appetizer, turned out great!
What it comes down to is the person has to want to expand their eating habits. I realized I was being kind of a baby about different foods, there are people all over the world brought up in totally different environments from me, and as far as I know nobody's starved yet because they hated everything but fried chicken and hamburgers but were born in Asia. In fact, most civilizations have built their food culture on things completely different from ours. Are they really all crazy, or is there something to it? That being said, she'll also have to "power through" a few things she doesn't necessarily love right away. Taking one tiny bite of green pepper and declaring you hate it but tried it so that's that isn't going to get you anywhere.
If your spouse doesn't want to change, she probably won't. It might be worth talking to her about her health, but I don't know what kind of person she is. I know in some of Jamie Oliver's videos he talks about getting kids involved in gardening to get them to try new things. Give a kid a carrot out of a bag and they won't touch it, have them grow that same carrot and they're excited to try it. There's a whole world of food out there, and believe it or not, the food that is on kids menus in American restaurants isn't the pinnacle.