I agree that counciling is definitely in need for this situation - but it will only be benificial IF the husband is actually willing to go. Men tend to shut down and go into avoidance mode after something happens in a relationship. They prefer to ignore or push the problem away instead of actually standing up to it and addressing it and finding a solution. You do have to admit though that this is a pretty selfish solution - just getting out of the marriage isn't going to make the fact that he has a child with autism go away.
I'm sure because it's only been 3 months, this is all still very shocking to him. I admittedly was extremely depressed about the sitation and I will even go so far as to admit that I was upset with my choice in a husband. If I had not been with him, I thought, I wouldn't have a child with autism. I could be raising a healthy family instead. Of course I've come to my senses and realized that I can't put the entire blame on him - I could very well have had an autistic child with someone else. Part of my blaming was due to the fact that my husband traveled a great deal for work and the majority of the time I was at home alone with my son. It's not a good thing to have the responsibility of being the ONLY ONE to take care of a child with special needs - I know many times I thought I was gonna go nuts. What is needed is a team effort by BOTH parents to take care of a child like this especially in the beginning stages. It not only helps for raising the child, but it shows the child what a family unit is.
I know a big reason your husband is drawing away is because when you get the autism diagnosis, you automatically think your child is doomed and will never live a full life. I felt this way for a long time - I couldn't envision the future - it felt like I was forced to take care of an infant for the rest of my life and there would be a stigma attached to him. It's been about 2 years since we knew something was very wrong with him, and it's only been a year since we got the official diagnosis of autism, but my son is now SO MUCH better than before and with his speech therapies, public schooling in early childhood classes, occupational therapy, special behavioral control (we use a pass system to control some obsessive tendencies he has ) and just time itself - he's beginning to mainstream. Our goal is to eventually control his undesirable behaviors and get him socially acclimated to the point that no one else will know he has autism at first impression. I warn you though, it's a tough road at first because the raising (and teaching) of an autistic child is completely different for raising quote unquote "normal" children - but it's just as rewarding - in fact, and here's the secret - it's more so.
Perhaps it would do your husband good to read about a woman named Temple Grandin. (type that name into your search engine) She's a PH.D, an assistant professor at Colorado State University, an inventor, and she is autistic. Her story gave me hope for my son and made me see that he's going to get older, wiser and learn to cope with his disability. I suggest you also print out your message and the answers you've gotten from other parents here to show him that you and he are not the only parents in the world with an autistic child.....your child hasn't been given a sentence to be doomed in life - you merely have to find a different way to enable him to learn things. Just because you have a child with a disability doesn't mean you shouldn't push them to perform to the best of their abilities.