I don’t think divorce is always the fault of both - nobody is a mind reader and sometimes one partner checks out or has their own, more secret life they keep hidden. There are tons of ways a marriage can become one sided and become a losing battle for the spouse who is still invested. It’s really clear that purpleraven did everything she could, so please don’t blame her for his decision to leave. None of us control anyone except ourselves, after all.
OP, I’m really sorry you’re going through this! I can’t give much advice, unfortunately, but I have heard of similar cases where husbands with (suspected) autism refused to get tested/have therapy. Why, I’m not sure, but you’re definitely not alone in this. I’m sorry I can’t be of any more help but I wish you luck in finding the support you need. For what it’s worth I don’t think your request was in any way unreasonable.