My ADHD Spouse Won't Get Help

My husband and I have been together for 11 years, married for six years.  When we first met, I was a fixer who liked to rescue people; we definitely complimented each other.  Over the years, I've done my own mental and emotional work to heal and grow; I don't try to fix or rescue people anymore and continue on my journey of personal growth.  My husband did two tours in Iraq and has mild PTSD.  For years, I chalked up his explosive anger to PTSD and his forgetfulness to an undiagnosed TBI (he refuses to get tested).  He was diagnosed and treated (Adderall) for ADHD two years ago when he started graduate school.  I didn't realize how ADHD affected relationships; I've always thought of ADHD as a focus/concentration problem.  Six weeks ago, I came across Melissa's work and realized that his ADHD better explains his symptoms than PTSD.  Since then, I talked to him about how his ADHD was affecting our marriage and how unhappy I am.  He agreed that we needed to work on our relationship and he needed to address his ADHD symptoms.  We started by buying a copy of Melissa's book and listening to the same book on Audible during a weekend getaway (we only got through half of the book).  After arriving home from that getaway, he has done nothing else to help/treat his ADHD.  I think he assumes that since we don't fight (I avoid conflict with him because I can't tolerate his angry explosions), everything is good in our relationship, but it's not.  He says he will finish Melissa's book, but instead, he spends hours and hours on the couch most days scrolling Facebook or watching TV.  I've asked him to find a psychiatric provider in our area who specializes in ADHD, but he hasn't (I found one in five minutes).  I've asked him to look at several apps to help him, and us as a couple, complete household tasks, but he won't.  I suggested Melissa's couples seminar, but he showed no interest.  We haven't had sex in over five years, and when I bring it up, he blames me.  He graduates his program in May 2025 and I've decided to divorce him if things don't change.  I love him, but I can't and won't live like this.  I'm going to suggest Melissa's couples seminar that will begin sometime in 2025 as a last-ditch effort to turn things around.  If he blows that off, I don't know what else to do.