I find if you plan ahead you can still enjoy going out sometimes. I'll go over the menu of various restaurants online and find what I could tweak so I could eat it at a couple of places and then let whoever I am going out with pick from those restaurants. That way everyone has options.
You also have to remember that you CAN ask for things to be done to meet your needs. When I went out with friends for Mexican, I got a salad without the meat, cheese or dressing and used salsa as the dressing. You can also ask for things without the bun or if you want it on a bun without butter or dressing. There are a bunch of articles on "dining out" on Spark. Check them out. They might give you some ideas. It's nice to be able to go out sometimes.