Start by telling her how much it bothers you, and how much stress it's creating for you. Say you don't care who cleans it, as long as it's getting clean. I hate ultimatums but maybe it's time for one. If this house isn't in shape in a month, were hiring some help.
It's fine to be proud, and it's fine to have some shame - but neither are getting the job done.
Is she working? If not, then no excuse. Either she cleans or someone else does.
Sometimes you just have to make the call, and she can deal with it.
Now let me pull my foot out of my mouth