Navy I know I don't comment often on your stuff, but the walking on eggshells comment spoke out to me.
From personal experience the more you walk on eggshells the more sbe'll expect you to. Which in turn makes you more nervous, and more likely to break them.
I used to live in fear I'd do or say the wrong thing.
Next time she threatens divorce over a trivial thing, just tell her that you love her and want to stay with her, but if what you did is so important that she would threaten divorce then maybe you should.
Be prepared because she most likely will throw a huge fit.
I know I've said this before, but your w probably has it figured out that you'll do and put up with almost anything to keep the marriage. So she knows she can get away with treating you the way she is.
I think you need to take a stand and demonstrate to her you won't tolerate her behavior. Chances are she's bluffing.
If she's not think about it this way, do you want to spend the rest of your life with someone who threatens divorce at the slightest provocation?