Husband does not accept that he has ADHD

My husband and I have been married for 10 short months. We are both in our early 30s. We had a whirlwind relationship and he decided after less than a year of dating that he had to marry me immediately, Prior to our marriage, I had frustrations with his behaviors and always wrote them off that he was "eccentric" and his frequent disconnections would be cleared up once we were married and living together. Only, in the last month have I realized that my husband has adult ADHD. The past few months had become very frustrating, he will spend hours in front of the computer "researching" and I felt like I had become the nagging wife I never wanted to be. I began to feel like he was no longer attracted to me and our sex life went from one of a newlywed couple to almost non-existent. I began beating myself up, feeling like I was doing something wrong and we would fight about sex more than we would have it.

Then he began having fits of rage over the smallest frustrations, to the point where I felt like I couldn't even communicate my issues to him. He has never hurt me, but when he feels frustration with work, or our relationship, he breaks his collection items or things that mean something to him, almost as if he is punishing himself.

I found myself, blaming myself for this behavior, even though he would tell me time and again it wasn't me. The most recent behavior he has begun to display is one of very low self-esteem and a sense of underachievement. For weeks he has not been able to focus on anything except for how he feels he receives no respect at work, and what he should have done different in his career path. He spends hours taking notes and thinking about what he needs to do in his career to gain more respect and get his "big break". I wanted to support and help him, but I didn't know how. I am a very patient person, but I couldn't stand seeing him sad, anxious and frustrated anymore.

I finally consulted with a close family friend of my husband, who is his "second mom". She explained to me that he had been diagnosed with adult add in his early 20's and that he and his parents had been in denial about it and he never properly took his medication. He just self medicated with marijuana. That was the only way he knew to stop the "racing thoughts" in his head and relax. He has since stopped the marijuana use, but I am scared he is going to go back to it because it is the only thing he thinks will help him "calm down".

I have begun to research adult add/adhd and it has helped me understand him and be a more patient spouse. I feel so lucky that I learned this early on and was able to find websites such as this one, to help educate me so that I can have a more successful marriage. But the hurdle I am currently facing is, how do I get my spouse to realize he has this disorder and that he doesn't have to live in this alone? His "second mom" has contacted him and has been trying to counsel him about his current issues and has suggested that he seek therapy or medication for his adhd, but he continues to insist he is not adhd and he is just stressed. I would like to help him, but I feel as if he has to acknowledge his disorder first. How can I help him accept and acknowledge that he isn't crazy and that he really just has a disorder that can be treated and that I can assist him with?