Broaching the subject

I am, like many people here, completely at my wits' end.  My wife has every ADHD symptom in the book, or at least one version of it (primarily inattentive type).  I am terrified when she gets behind the wheel of a car.  She stares at her iphone, playing mindless self-medicating games, all day long.  She is as sexually dysfunctional as a rock.   She hums all the time.   She does few chores on time, and if she does, is openly hostile.  She finishes almost nothing.  She is never on time for anything.  She feels "overwhelmed by life," this despite the fact that her life is about the cushiest one out there.  She can't get out of a grocery store in less than 500 years.  She is brilliant but hates having a job.  (She left the workforce long ago; people continue to offer her jobs and she always says no).  She never goes to bed and yet complains of being constantly tired.  She overspends.  She loses her keys, her wallet, her purse, her phone, the book she was reading (and would never finish).  One time she put her keys in the meat drawer in the refrigerator.  She doesn't hug the kids, who are spectacularly lovable and worthy of hugging.  She is "tired of being the mom."  I don't doubt that it's hard being a mom, but our kids are a breeze and I work at home and am always around for chores, pick-ups, and the rest.  In sum, she she feels totally absent as a personality in the room except for an aura of fear, distraction, and a zen-like, self-protective tuning out.  

 The situation has worsened as my daughter has grown into adulthood; my daughter, like me, is highly focused, energetic and organized, a straight A kid with a bedroom as neat as a pin.  She is also hilarious and a gas to be around.   My wife feels like we are conspiring against her, and we are, in a sense; the two of us spend an awful lot of time managing her mother and venting our frustrations.  We delight in doing chores together.  One game we play is doing the grocery shopping with the rule that the cart cannot stop moving.  We go out together for coffee, walks, to the movies and the gym because, as we both know, making plans like this with my wife is pointless; we'll never get out the door.  We are like a couple of soldiers in a foxhole under heavy enemy shelling, telling jokes to pass the time.  This has saved me, but it's not fair to my daughter, whose heart is broken by her distant, unloving mom, who cannot so much as accept a hug, let alone offer one.  A girl needs her mother, just as I need a partner.  My daughter leaves for college soon.  She says she can't get away fast enough.  I already miss her.

Like many people here, I have reached a breaking point.  I love my wife dearly; at her best, there is no one better.  But I am angry, lonely and depressed all the time.  When I come home, and my wife's car isn't in the driveway, I have three thoughts.  First, my heart sings a little.  Second, I am terrified she's been in an accident.  And third, I rapidly calculate the odds that either of our children has been in the car with her, praying that, at the very least, her texting and driving and thoughtless lane-changing have killed no one else.  That, in sum, our family has not been obliterated by her distractible neural pathways. 

My wife will grudgingly concede that she has ADHD, or at least entertain the idea.  She just won't do anything about it.  For a brief period, just a couple of weeks, she took medication but abandoned it, claiming she didn't like it, and indeed it made her very snappish, though more effective in the day to day.  I would welcome advice on what to do next.  How do you lead someone to the realization that this simply has to be dealt with?  That, in effect, she--not me, not the kids, not life itself--is the problem?  At what point do you issue an ultimatum (even if it's false; I really can't see ending the marriage)?

Many thanks.