Help with Understanding ADHD versus ADD

Hi, I'll start with some background history: I've been married for 5 years now and when my husband and I first met he told me that he was diagnosed with ADD when he was a child but his mom who is diseased now said that he didn't have to take the medication prescribed. In telling me this he also said that nobody in his family knew being his father and his older sister.  I figured he told me because I am his wife, he really didnt get into detail as to why he told me. But reading some of the personal experiences on this website, it seems as though he may have ADHD too or instead. I am no expert that is why I am looking for help because many time I wanted to leave my husband because he seemed to be cold and distant. He says its because I broke his heart with my behavior towards him when my behavior is because I don't want a divorce but that I am at the same time being exhausted with what I have to take on myself because he is not supportive emotionally. I must say reading the post on this website has given me hope in my marriage. There also may be a possibility that my son may have this as well, but I withheld that information about my husband when asked about family history with ADD, I wasn't sure what to say as it seemed to be a secret. My son is in an ESE program getting speech, occupational and behavioral therapy since he was 3 years old. He has an IEP  if anyone is familiar with that. I was thinking of revealing this to his ESE coordinator at our upcoming evaluation because I don't want him to be ashamed as if it is something to be embarrassed about so that he can receive the help he needs throughout his life. Also because I see my husband now and how he may very well be in denial that he needs help. I just want to do what I can to be supportive as well as educated so that I don't burn myself out or rehash things that don't need to be repeated and look to a divorce as the only way out. So does anyone have any suggestions as to where I should start, my husband was diagnosed with ADD but this forum addresses ADHD and alot of what is shared here I can relate to in my marriage. Also this is something I can't discuss with his doctor because he doesn't have regular appointment, he just received health insurance at his job. My son has his own health insurance and I dont have medical insurance but receive the help I can get through the VA. Thank you in advance.