Sliding back or getting perspective?

Yesterday morning I talked to my dh for about half an hour.  It was nice to talk to him again.  I know, I know.

I've been thinking since.  Something I am really having difficulty with, and which I can find no information or advice about, is his diagnosis of PDD-NOS/ atypical Asperger's Syndrome.  I am on an 'emotional abuse forum' which is really helpful and supportive.  But often I just don't see A in the descriptions.  His behaviours have without a shadow of a doubt been abusive, but I'm not sure the motivations and some other aspects are the same as 'usual'.

A number of things make me say this:

1. The physical violence never escalated.  There were 3 incidents (including the sexual violence) over the 14.5 years that we were together.  The last time almost 6 years ago.
2. He has never denied his behaviour. 
3. He is not a 'different' person with other people. 
4. He has seemed genuinely horrified to find out that his behaviour is generally thought of as abusive.

Number one there on the list is pretty self explanatory.  Everything I've read says that if a man is physically abusive it will escalate in severity and frequency.  Neither of those happened.  So, it makes the doubts start to set in.

Number two - well, he has never denied things he has done with the exception of sometimes he denies remembering things that he has said.  This is difficult, because the psychologist who diagnosed the Asperger's explained how it has been shown in brain tests that during heightened emotional exchanges (arguments usually) the part of the brain responsible for laying down memories to long term memory closes down in order to divert energy to processing the difficult emotional reactions.  There was a neat, scientifically proven reason why he didn't remember things he'd said in the 'height' of an argument.

Number three.  He does have a different persona with people he has known for a long time.  When his mum is around he is Super Dad and Super Husband so she has a slightly skewed idea of what he does around the house.  He doesn't talk different or act differently towards me or anything.  We have always acted the same together around everyone else as we do on our own at home.  Is this a sign that his behaviour is not conscious but in fact just part of how he is wired?  Oh, he also acts like a prat round his best friend (from school) but again, I find it hard to believe that most guys don't do that?  At least when they are younger.

Number four.  Again, this could be an act.  I don't know.  But when he read The Book he seemed to genuinely have an epiphany that his behaviour towards me was not just 'normal' (apart from the physical abuse which he has always known and said was catagorically wrong) but in fact most people would describe it as abusive.  He seemed shocked and acted immediately - researching different abuser programmes, told his family and friends and has even brought the book for each of them to read.

So, this all leads me to feeling confused.  On the one hand his actions are definitely abusive.  On the other hand there are a lot of questions running around my head.

Is it that a boy born with a slightly different wiring that meant he could not easily see things from other's points of view and had very inflexible thinking (very difficult to change his mind) was unfortunate enough to grow up in a house with an emotionally abusive father that taught him that it's perfectly OK to belittle your partner, demand things from them, criticise them, have control over what they do with their time and so on.  Observing this family dynamic, would a child with Asperger's internalise that as a normal, desirable relationship and then as an adult the in-built lack of empathy and inflexibility mean that he also can't help acting in an emotionally abusive way? 

Or does it just not matter?  Should I not be trying to figure out what's going on in his head?  I guess the thing is, I'm wondering if there is hope here.  There seems to be little to no hope of abusers genuinely changing.  I'm just wondering if there might be, because it's not just black and white.  But is it ever? 

Oh, it's all confusing and I'm falling into the trap of over-thinking and trying to fix our relationship instead of just getting myself stronger and healthier.