I am the house chef 90% of the time. I just make two meals. On stir fry nights, I have always stir fried the meat and veggies separately anyway, so that makes it easy enough. I just pull my veggies out before adding the meat back to the pan, and add a meat replacer for mine if I am going to (tempeh, soy curls, etc...)
My husband has recently come to realize he cannot and should not eat as much meat as he used to, which, believe me, is a wondrous thing. My adult disabled son lives at home, too (he is the secondary cook for when I am not home) and he has accepted my becoming vegan easily. I have long gotten them used to starches having veggies in them (even things like mac& cheese, which we rarely ate anyway) and transitioning to whole grain pastas, real potatoes with skins, meat-bean mixes, etc.
So your significant others might not be going as far as you, but perhaps your lifestyle and dietary changes can affect them still in a positive direction, and make you feel a little less like you're doing this all alone.