belligerance, blaming others

Why is so difficult to convince people with ADHD that they have a problem and get them to seek help?  It's astounding to me that after everything we've been through together, my husband still goes on the attack when I try to discuss help for him.  He's called me names, said hurtful things about my family and me, blamed his misbehavior on me...  Over the years, his ADHD has gotten worse, and yet I've stayed with him 20 years.  I understand defensiveness, but my husband is not a stupid man.  Why can't he see all the evidence and realize how much fuller his life would be and how much better he'd feel if he could just commit to treatment?  I'm exhausted thinking about the rest of my life and what more could happen to us.  I don't want to live this way anymore.  I just want safety and comfort for me and my kids.  I think at this point I just want a peaceful divorce, but I know it would devastate the kids and I know my husband wouldn't allow it to be peaceful.