I don't know how well this would go over in your household, but in my home this is what we do. I am newly vegan and dh is omni. For a long time I would make piggy back type meals, but it just wasn't working for me to plan a meat and potatoes kind of meal and then find a veg*n substitute for whatever meat dh was having. I was eating a fair amount of processed foods, and much more dairy than was good for me. So shortly after my baby was born I started planning complete vegetarian meals. I allocated a part of our grocery budget for dh to use to get whatever meat or dairy products he might want. If you wants to eat it he can prepare it.
To be honest at first dh was kind of grumpy about it. I kind of expected that, because not only is he kind of picky in general and really resistant to the idea of "hippy rabbit food", but he is also very resistant to anyone telling him what to do - I am sure he viewed my actions as a passive attempt to get him stop eating meat. While I would be thrilled if he decided to completely cut out animal foods, the change was mainly for my benefit. Being pregnant, and then nursing made me much more aware of the nutrients missing from my diet. I was very clear that although my main reasons for not eating meat are ethical and environmental - reasons that he understands, respects, and to some level agrees with - I had to be healthy too, especially when the baby's health was dependent on me being well nourished. And I told him that, and that seemed to help.
Anyway, at this point dh is only eating meat a couple times a week, and he is happily eating legumes and all manner of whole grains and veggies.
homemaker mama to and due in March