New Here - Husband with ADHD and do not know what to do

Hello everyone!  I recently started to research ADHD as my husband was diagnosed a couple of years ago and I feel that he is under treated.  Our eight year marriage had been on a steady decline and I realize we are both contributing to this, however, I had no idea the impact ADHD was having on us until doing tons of research recently.  I feel like I could have written, myself, so many books, & comments I've read from ADHD spouses.  To be honest, prior to reading all of this information, I was wondering if I was completely losing my mind and I have been dealing with overwhelming amounts of stress and anxiety.

A little back story - My husband and I have been married for eight years, together for eleven.  We have a wonderful five year old daughter.  I wouldn't trade her for anything, no matter what, but the decline in our marriage happened immediately after having her.  Currently, I am a full time business owner, wife & mother.  After having our daughter, he expected me to take our daughter to work with me, since I have some flexibility as a business, owner, and he did not want to contribute to pay for daycare.. it is expensive.  I did this for the first 5 years of her life, prior to school starting.  I managed, somehow to keep the business alive while watching a child at the same time.  I repeatedly tried to discuss daycare options telling him I was drowning.  He would completely ignore my request for conversation or completely lash out... going straight to "f you" "get the f out of here" and screaming in my face.  All "what I feel" should be normal discussions (bills, future plans, child care, even potential fun like vacations) are reacted to in this manner, so I am basically afraid to talk to him about anything and have definitely isolated myself from him out of fear.  Aside from child care & running a full time business, I do all cooking, must keep every detail of our lives in order or it just won't happen.  If I do ask him to contribute something, such as mowing the lawn, which I've even tried being extremely mindful of how I ask, I am normally, however not each time, met with complete defiance and a crazy, back and forth ensues.  I feel like these tasks are just things that need to get done and I don't understand the energy wasted on fighting over them.  I work a lot and a lot of weekends in my busy season.  I will be gone for 10 hours sometimes, on a Saturday, and I can come home to absolutely nothing I requested him to do being done.  He will often come up with unrealistic excuses as to why they weren't accomplished.  He will watch TV all day with our daughter, to add pain to nothing getting done, and it could be eighty degrees and sunny that day.

 I just feel so overwhelmed, exhausted, frustrated and basically like I have to handle everything.  On top of this, a few years ago, he borrowed money from his retirement account, thinking I wouldn't find out, but I handle our taxes.  I had to pay the taxes on this money for him.  I'm always scared.  So frightened that I can't trust him, that our futures are not secure.  He always tells me he is going to accomplish things and to do things that he never does.  Then gets infuriated when I try to encourage him or even try to make plans for our future.  When we first met, we had a very fun relationship.  He told me all these dreams he had and I was starting a business at the time of my own, so the future seemed bright!  My business has grown, and he never did anything he said he was going to do and I guess I have a lot of resentment over broken promises, what I feel is so much resting on my shoulders.  To make it worse, he does not recognize what I'm experiencing at all...  What so ever.  He thinks I'm completely over - reacting.  This has been making me question my sanity.  He seems to think that doing all child care, while working full time and taking care of our house / cooking, should be completely manageable.  If anything he is scornful to me and calls me an "f'ing b*tch" when I bring up my unhappiness, etc.  

I was ready to leave, however, hesitant because of our daughter, but now I'm wondering if all of this is just really under treated ADHD??  He completely ignores me when I even try to bring up his ADHD.  When he was first diagnosed, a couple of years ago, he brought it up so quickly, kind of brushed it off, and to be honest, at the time, I didn't think too much of it!  Until I started to dig.  We have cyclical, repetitive issues that just never get resolution.  I had to take some action.

Thanks so much for listening.  I'm feeling very sad & alone and it's so helpful to read about people I can relate to.  Any advice is most welcome!