LD, after the holidays crashes like this are to be expected.
I mean, you're wound tighter than an 8 day clock for days & sometimes weeks prior to Christmas and then BAM! it's done.
The crash is normal.
Don't analyze it to death.

I am concerned that you still harbor expectations each time you interact with your wife. I know you say you don't but truly, search your heart, I think you do. And that is why you seem to crash so hard. If everything you do for your wife were really being done without expectation you would be happy just to have done it - not reeling afterwards and rehashing the details in your mind.

It is time for you to get up and get a grip.
This is my advice - and there will be some people who disagree with me - so decide for yourself whether or not you are ready to take it:

Don't do another thing for your wife.

I don't care if that donut spare rolls off into a cow pasture and she's got sparks flying off the rotor - don't rescue her again. She needs to see what a piece of crap she has tangled herself up with so let her call him to save her next time. Don't give her money, don't pay her car insurance - drop her from the policy if she doesn't pay. If for some reason you have to switch the car into her name in order to do that, do what you've gotta do to make that happen.

Separate from her financially.
See an attorney.
I'm NOT telling you to file.
I'm simply telling you to consult with an attorney about a separation agreement being drawn up.
I am not an advocate of shocking a WAW into reality but your wife is skating on some real thin ice and I think popping it once or twice with a hockey stick would be acceptable in your case. Don't do anything rash but don't hide the fact you are seeing an attorney either (if you decide to do so).

So there's my advice.

Pray about it before you do anything.