Irresponsible Husband

My husband and I have been married for almost 9 years.  We have two children...the youngest is autistic. My life is extremely stressful.  I strongly suspect that my husband has ADD.  Trying to get communicate with him is a very frustrating process.  He often leaves out a lot of the details when it comes to topics such as finances.  I'm left trying to fill in the gaps of what really happened.  His explanations often don't make any sense and sometimes he lies.  His memory is very poor...he'll swear up and down that he doesn't remember the details to recent conversations. There always seems to be a problem with his paycheck or his checking account.  Basically, it's one wild excuse after another. 

Now, my husband doesn't take drugs...I know this for a fact.  I've read about the symptoms of Adult ADD and I'm convinced that this is what my husband has.  I've tried to get him to go to doctor to be evaulated and tested for ADD, but he refuses to go.  The strain of having an autistic child is very enormous and it's emotionally and physically draining.  I love my son with all my heart.  But, having a husband he can't seem to get it together is frustrating.  I often have to cover for his share of the rent (because there's always a problem with his paycheck or bank account) and I have to buy groceries most of the time.  Even though my kids have a father in the home, I still feel like a single parent.  I deal with the following drama almost every day:

His wallet or keys have gotten lost again

ATM Card lost or he 'forgot' his PIN number (can't access his cash)

Frequent bounced checks resulted in NSFs (can't manage a checkbook--I'm glad that we have separate accounts because I can't trust him)

Failure to keep appointments/obligations

Fails to set his alarm clock when he has to go to work:  I have to wake him up as if I'm his mother

I'm sooo tired of him...he's ruined my credit twice.  At the same time, I'm getting physically sick because of the huge toll on me everyday.  I'm experiencing anxiety attacks and having frequent crying spells...I resent having to be the one to pull nearly all of the  weight.  I wish he would get a second job, but he procrastinates a lot.  He's always finding excuses. I'm so sick of it.  Even when things aren't his fault, I find myself blaming him anyway.  I guess I've become numb to his excuses and don't wan to hear it anymore.  I getting sick all of the time because of the heavy stress and my doctor advised me that I need to go on medical leave.  But, I'm afraid to do that because I can't trust my husband to handle the household expenses.  Whenever the rent is due, I always make it a point to give the payment to the landlord myself because I can't trust my husband with that kind of responsibility.  Years ago, when we first got married, I let him give the rent to the manager and somehow, they never received the money.  He lost the money order and we eventually, got evicted because of this mishap.  He's had his car repo'd twice and has had his wages garnished at least three times since we've been married.  I constantly have to remind him to do this and that.  It's crazy!!  At this point, I just want out of the marriage.  I no longer respect my husband...he's suffocating me.