Filing for Divorce and believe my spouse has undiagnosed ADHD

I don't even know where to start. I don't want to disparage my wife, but I have paid over 1/2 the retainer to my attorney and plan on paying the rest by the end of the month so I thought I would at least put the information out there because this all just seems like a bad dream.  My wife and I have been married for three years, she has two children (6 and 7) from a previous marriage.  I feel like I have three children and just myself in the marriage.  Like I said, I have no idea where to start.  My wife refuses to be evaluated either for depression, ADHD, or any other medically valid reason why she exhibits the behavior she does.  For example, she cannot make a decision without a great deal of input from me, she calls me (until I was recently reprimanded for her calling too much) at work at least 15 times a day for advice on basic decisions, recently we spent over two hours discussing plans for a birthday party for a six year old.  We will arrive at a decision and she will change her mind at the last minute, leaving me completely dumbfounded as I plan for one thing and we end up doing another.  Up until I informed her I was filing for divorce, we had little to no sex life at all, twice a month was a good month, strangely since I informed her I was filing that has changed to she seems to not be able to get enough (she says she is so sorry for denying it in the past).  She is a stay at home mom yet until I informed her I was filing housework was hit or miss, but most of the time a miss, I would often remark to her that I was more impressed by the amount of work she "didn't" get done.  I worked part time and full time, and am in the Army Reserves, and I would come home to barely walk through the living room because of the mess and do the piled up dishes in the sink.  She says she gets distracted and she watches videos of old TV shows a lot on her phone, so on.   Maybe these things seem minor but my confusion lies here, she can concentrate when it comes to school activities, volunteering for EVERY children's event at school, organizing and planning them, she will spend hours.  But she says she is always overwhelmed when it comes to housework, the only thing that engages her is me becoming upset, (I am not a person to yell, but I do get frustrated about it), or recently when I informed her I was filing for divorce.  This may seem minor and some may ask "why is he filing for divorce just because she doesn't clean the house", I wish it were that simple.  It pervades every part of our life, work, home, church, school, and family relationships.  Simple things that seem like every day events for most of us become monumental tasks that she needs guidance through.  She goes to bed about 8:30 pm and gets up just in time to get the kids to school, around 7:30 am, which causes chaos because they aren't able to get ready in time and she is constantly running late.  Many times I have over 10 calls at work in the morning between 7 am and 8:45 to advise her how to handle a situation with the kids, so on.  I have detailed discussions with her about either an upcoming event or even just a small event later that day and she literally will act as if we never talked an hour later, and forget remembering a detail.  My confusion is, if it concerns her children she knows down to the 25th decimal point of PI.  She has been evaluated for a sleep disorder, lupus, any kind of vitamin deficiency, and nothing has been positive.  The chiropractor believes that she may have Adrenal Stress Syndrome, he recommends two chiropractic appointments a month, I researched it and it isn't even medically recognized, so I told her that makes no sense to spend all that money on something there is no real diagnosis for.   She finally agreed to be evaluated for the possibility of Adult ADHD but hasn't followed through on an appointment, she wants me to schedule one for her!  I am still proceeding with the divorce, but does this sound familiar to anyone.  I believe it is ADHD but since she won't get evaluated, I cannot be sure.  It's been a nightmare during the time we have had together and I just can't carry three people through life anymore when one of them is making adult decisions without the ability to contribute to the marriage.

My struggle is how can she focus on her kids, but have complete chaos everywhere else?  I don't understand that.