My first month in Al Anon, there was a guy who was a RA who was recovered for 18 yrs. When I shared my story about my, now ex, who was in his first yr of sobriety but not working a program, this guy said to me "He's a dry drunk, put your seatbelt on, you're in for the ride of your life"
He was right!
Sounds like your H is replacing his drinking with writing. Addicts have to be addicted to something at all times.
Is he working a program like 12 steps?
And yes, being in Al Anon to keep the focus on you is a great idea.
It's REALLY hard, but you need to learn to detach.