I am so sorry for your situation - your dynamics appear to be very close to mine / same age, time married/together. Some of it sounds like mid-life crisis. You might find some good information on those threads.
Take care of yourself first - it won't be a quick fix.
Irish
M-48/XH-48 M=25/T=28 years Ds-24,22/S-18 D - 3/11 A Day at a Time