eoe,
I grew up vegetarian in a house of omnivores. I live on side dishes. Isn't there anything that your wife will cook that can either A: have the meat/dairy left out of some of it or B: can have meat added just on top or something? If you can isolate the meat to one part of the meal, you can easily leave it out.
Like, make baked lemon chicken and have rice, salad, a veggie, etc, as side dishes, then cook a veggie burger pattie for yourself and mix it into the rice with some salsa or something.
If she wants to have mac'n'cheese, have her leave some noodles out plain for you, and cook yourself up some peanut sauce and veggies and have fake Thai.
Make vegetarian chili and brown some ground beef on the side. Or even better, make the chili with TVP in it and I bet they would think they were eating meat (it's lightly chewy, but has no taste) Make shrimp alfredo and leave the sauce on the side. Have a breakfast night with pancakes made with applesauce, fruit, and some veggie-sausage (odds are your family would never know if you didn't tell them--and if you didnt eat it either, if you're avoiding meat-like substitiutes--you could get them liking soy!!)
Or have family salad bar night, where you have a billion toppings to choose from (carrots, celery, beets, sunflower seeds, cucumber, broccoli, cauliflower, peppers, olives, spinach, garbonzo beans, AND cheese, grilled chicken strips, and bacon bits...everyone can put what they want on it, and you can just leave out the meat/dairy!
Compromises like that are what I'm accustomed to doing all the time, and it normally works out quite well. There's a billion ideas!!!