wife preparing to leave me and kids

[Jack_Three_Beans]

You're already getting some good advice, the only point I would like to make is:

so anything I do now would seem disingenuous

Depends on your intent.

If you are doing something just to trick her, just to get her back?
Yup it is disingenous.

If you are doing it because you realize that you should have been doing this all along and actually want to and plan on keep doing it?
It is sincere.

While she may think it is disingenous, you can only prove it is not over time and you only prove that by making it a true change to your behaviour. Over time.