As someone who is in a similar situation (weightloss with a spouse and mental health issues to work on), I recognize a lot of what you're saying here. When we decided to lose weight, the same thing happened to my wife and I- I lost 20 lbs on Keto almost immediately, and she did not see the same kind of results. There are three things I found helpful to keep in mind in this situation:

1. Weight loss isn't linear- I plateaued after the 20lbs mark, and there will probably be a point where "lazy" keto does the same for you. It will be different than mine, but it'll happen.
   
2. I had more to lose to start with- this was the biggest comfort for her.
3. The scale is not your friend when it comes to really measuring progress. I am down 20lbs, but 3 belt loops for example.

TL:DR- I think it's awesome that you want to be supportive to your wife, but don't derail yourself for her sake. Remind her there are other ways of measuring progress, and it is a marathon not a sprint. Good luck!