I had PTSD symptoms for quite awhile after d-day.
I tried a little of everything- De-stressing through yoga, exercise, lots of hot baths. In the early days post d-day when I could not sleep- I would take a bath at 2am!
Going to IC was very helpful. I needed to discuss everything about the trauma of the affair over and over for it to finally lose that hold over me.
I also went for EMDR.
A book that helped me also: Transcending Post Infidelity Stress Disorder by Dr. Ortman.
My FWH had a 5 yr LTA and even though we R after 6 months of separation it wasn't until 4 yrs post d-day that I started to see the light at the end of the tunnel.
It takes a long time to 'get over' infidelity.
If only the WS realized this when they embarked on their affairs.....