I still do not like my food touching, but I have learned how to deal with it.
Even today, when different types of food are on my plate, I will mound them up so the same stuff is in a bigger heap farther from the other heaps. Gravy does pose a problem... I do not like that it travels around my plate and touches food I don't want it to. Or, too much gets soaked into the right thing.
For me, it is texture-related. I like a *certain* amount of gravy on my food. I want the flavor and a little moisture, but I don't want my food to get soggy from too much gravy. I *deal* with it if it happens. But, I don't like it. I have just learned not to freak out, and I don't go out of my way to do things that would be obviously different from most adults. If I was in my own dinner world, I would probably have the gravy separate and dip my forkful of stuff into some gravy to get just the right amount.
When I was a kid, I refused to have more than one type of food on my plate at one time. I would dish out one type of food, eat it. Then dish out the other type and eat it, then the next and eat it. This is actually a very bad approach because one will almost automatically overeat if one is required to eat all the foods (instead of getting a little bit of each until one is full.)
For a while, my mother had me using divided plates, but this didn't work either because I would still eat the different foods in turn. I could not move back and forth from one food to another.
This all started to change when I was 17 and started dating my now-husband. We would go out to eat (I would make him order for me because at that time I still couldn't talk to the waitress.) We would get our food, and I noticed that he would taste each of the things on his plate, whereas I would eat all of one thing at a time. It became very obvious to me that he was doing something "normal", and I was not. He didn't make fun of me (though he noticed), but I was a bit in awe of him - how could he do that? I gradually got up the courage to try eating his way. Now, I am used to moving back and forth between different types of food.
The only type of food I don't mind touching - and will actually mix - is Indian food.
When things touch or the texture (or taste) is something I don't like, I must fight the gag reflex, which is more psychological than physical. I can feel the sensation without actually feeling it.
Last week, I was going to vomit if I had another sandwich (that is a long story about issues with sandwiches), but my husband chuckled *with* me when I said I COULD NOT eat another sandwich. I had to get creative with lunches last week since I had to bring food with me various places. Yesterday, I was finally able to eat a sandwich again. Now, I need another rest from them...