Is divorce inevitable if we have the same vicous cycle?

My husband and I have been together for 7 years and married for 5.  We have a 5 year old son with autism and have an 8 month old daughter.  Life with my husband has had many wonderful moments and I find myself loving him time and time again.  He holds a job and has held a job our whole relationship and I know statistically he is an anomaly.  I should also mention that in the last two years he has begun the meds dance with anti-depressents and stimulants.  He also suffers from OCD, tourettes, and of course ADHD.  We have also been wondering if he might be autistic (him and I) as we recently went through the autism diagnosis for our son and he realized that he has many of the same tendancies as my son.  He toe walks, has trouble with eye contact, recoils from affection (sex has to be in the dark - he enjoys it but doesn't want me to see him naked).  The list goes on and on and I have simply come to a place where I have gotten used to many of his rules and differences from my girlfriends' spouses.  

I am the breadwinner and I know I always will be because he cannot finish a college course and has never been one to impress his supervisors at work - he keeps himself right under the wire in terms of keeping his job.  His current job he has been passed up for a raise at every opportunity due to not making adequate progress - he blames his coworkers/boss.  

I think about divorcing him every year and every year I talk myself out of it - I find a way to forgive him/justify his behavior/work on our communication/blame myself.  2010 we lived in Abu Dhabi and I taught and he stayed at home with our then 2 year old son.  We fought constantly.  He did not do a thing to lift a finger around the house and retreated to his online role-playing as soon as I got home every day - calling me on my way berating me for not leaving work sooner.   He told me during that time that he never loved me.  We decided to move back to the states to get early intervention for our son and I realized for us to work I needed him to work so I wouldn't resent him for spending all my money and not lifting a finger at home (no cleaning, no meals nothing).  My bonus was then used to purchase his well researched an obsession for many months, the MAZDA speed 3 hatch.  And thus started his auto-cross racing obsession while I worried endlessly about our next home/my next career/and diagnosing our son's autism he thought about modifications for our "family car" to race.

I was hired sight unseen to teach in Alaska.  We moved again to the middle of nowhere in terms of friends and family and I have to say that again this feels like a huge contribution to our marital issues. I began the job of my dreams and he found a job.  He started racing his car and had to replace his clutch within weeks and the money pit mazda speed began.  I bought a 4500 suburu and never had to put a penny into it while I watched every extra penny go into performance parts that were a must.  He begged/pleaded/insisted and when I resisted I was the bitch.  Each argument I felt like I was spinning.  I became pregnant and turned to this forum in the first Alaskan winter with my hormones at full speed.  I was ready to leave him.  not sure where my posts are but if I were to circle back to them I know that there was some serious issues in our marriage that we went to some counseling and we moved past.  Now add a baby to my full - time care of my son and life got more complicated.  He cannot handle the kids on his own.