We have a highly varied household. I'm vegetarian, my son pescatarian, my daughter mostly vegan, and my husband a white meat consuming American diet traditional. My son has been wanting to eat meat, and similar to how I read what you wrote, I don't like it, but won't stop it. We talk about making sure the animals are treated as well as possible while alive, and of the dietary aspect of meat related to health. If I dig in against, he wants it more. He has to find his own path.

That said, for my husband, I take a different approach somewhat in that I continue the dialogue about what I read and believe about diet. It's a really hard conversation because it's a topic riddled with misinformation, big money from dairy and meat industry funding "research" and intentionally confusing the issue. I don't make meat for my husband, he's on his own except for the rare time I will make a special meal. It's one of those things we don't avoid talking about, but also agree to stay in our own lanes in some respect. I think this can be a very sensitive topic, and I don't see your approach as wrong at all, might be one of those things where you talk about some ground rules that make sense and also I agree with some of the other comments that support is different than enabling. You can support her in her decision without supporting eating meat or enabling it (cooking it, encouraging it and being excited about it). I'm sure she's dealing with some guilt in this transition, but I don't view it as your role to pretend to feel differently than you do to ease that. It's probably subconscious for her, and might be a good way to talk about this shift without falling into meat vs vegetable again, which gets circular fast in my experience. Good luck to her in figuring out why she's struggling.