Is leaving a spouse with ADHD like leaving a spouse with some other disability?

I've been married to a wonderful man for 4 years, together for 6. Like many non-ADHD spouses, I was attracted to the spontaneous, child-like, fun qualities of my now-husband and felt that "opposites really attract". However, since being married, the effects of his acknowledged (but untreated) ADHD had corroded our marriage and turned me into a bitter, angry, sad, and anxious wife who is ready to leave. My husband teaches students with behavior disorders, so he knows all the signs and coping mechanisms to deal with his own ADHD, but as of yet, refuses counseling, medication, or strategies to make our life better. I'm a total type-A person who has taken on the majority of responsibility in our lives, and have become someone I barely recognize... I never laugh, never smile, and generally think depression is a factor in my life. I now want to have a child, but can't fathom the idea of having a child when I feel as though I'm already raising one, and do not want to bring a child into a home that is so disfunctional and broken. He is a good man, with good intentions and a good soul; but his habits, lack of motivation, and inability to follow-through has driven me to the breaking point. I feel incredibly guilty for thinking of divorce, because if ADHD is really a disability (as my husband claims), than I am a rotten person for not staying to support him? I feel as if life is too short to be this unhappy, and I sincerely doubt my ability to support him long-term with these challenges. I've tried many suggested ideas, such as lists, schedules, reminders, etc, but nothing seems to work and I just don't want to try much more. He says I've checked out of the marriage, and I think he's right. He says if I just love him enough (more) things will get better. I think it will take more than love; from reading other posts, it seems like it takes a lifetime of patience, extra effort, and more patience, which frankly, I've never been in high supply of. Any thoughts on my predicament?