I recognized the reference from your thread title immediately. I've read LOTR at least a dozen times, along with the rest of his writings (and his son's).
Yes, PTSD is common enough for betrayed spouses. Therapy will help. Time and some work on healing are the best remedies.
I'm over 10 years out from d-day and I am as healed as I can possibly be. Memories fade. Although we divorced, for lots of other issues besides infidelity, we're still good friends and i still love her (not enough to want to live with her, but that's another story).
I don't think the average betrayed spouse endures anything even close to what Dear Mr. Frodo experienced.
Your wife will heal. There will come a time when she doesn't think about it, doesn't feel it, and a daily smile will return to her face and eyes.
For most betrayed spouses the affair was bad enough. It's all of the lying, blame-shifting, minimizing, gas-lighting, and the rest which often follows that does the greatest damage. With none of that happening in your situation you're way ahead of the curve.
One of my favorite poems is by a preacher named Max Ehrmann. "Desiderata" I read it several times a year. In fact, I think it's time I start another thread in the General forum (yes, I've done it before).
Married 2005
D-Day April, 2015
Divorced May, 2022
"The Universe is not short on wake-up calls. We're just quick to hit the snooze button." -Brene Brown