As williamkelvin said, deep validation is not agreeing with her, it is acknowledging that her feelings are real, understandable, and that you notice and care about what she is feeling. And that will help her learn to acknowledge and ultimately manage her feelings.
Will she ever be able to manage her own emotions or have I took on a life long job of constantly validating, managing emotions, explaining the obvious and deflecting the abuse and anger?
That is a good question. And hard to answer if she will ever be able to do that or not. Perhaps she never will do it very well, but it is definitely possible for her to improve at least some. I know my wife did.
Let me flip your question around, though.
She
never will learn to manage her own emotions as long as you keep doing it for her. Guaranteed.
You do need to protect yourself from the abuse, and remove yourself as the target for the anger. But don't try to deflect the anger or guide her out of it.
The only way she will find a healthy way to manage her anger is if you leave her to be with it and work it out on her own.
And this really is good news for you, Horus--you sound tired of trying to manage her feelings. So stepping back and letting her do it herself will help that!