You can't save it in all likelihood. She wants out so tell her to get out. It's the only hope you have of "saving" this marrige. But why save something where she doesn't love you anymore. That's the crux of it, instead of working to build a good relationship she didn't communicate until it was over in her mind.

Go to /r/divorce and read up on 'walk away wife'. Husbands can be equally shit too FYI, you're just on the receiving end this time.

Don't work together, buy her out or have her buy you out.

Don't play nice either, she won't and she's the one failing your partnership.

Let her go and find someone that will love you. It's hard as fuck to accept, I know. It took me over a year to move on mentally. 3-4 months to accept it at first, then longer.

Look back though, was she meeting any of your needs? Probably not.

Good luck. Love yourself and upgrade!