I tried talking to my ex so as to get some insight into his thoughts, but to no avail.
I told him I would like to understand how he could go from all that seemingly deep affection to treating me like dirt and making me feel like a stranger; I tried inquiring about what made him uncomfortable; I tried asking him about his needs. Calmly, in writing. The reply I got? "You don't need to understand anything".
How am I supposed to deal with this? Every attempt I make to communicate is pointless.
It hard, Aspies have a disproportionately larger Amygdala (part of the brain responsible for raw emotion) at a young age we(myself but using the royal we)are 'emotionally over reacting' to events and commonly lectured on how our feelings are wrong and disrupting others and shamed into controlling our emotional response.
One analogy is a pot of water simmering on the stove, for nuro typical as the temperature rises it starts gently shimmering and steam coming off. Other NT entering the kitchen can read the signs and lower the temperature.
For young Aspies, the source pan base level would be vigorously boiling, spluttering and spilling over. This distresses NTs and the child is scolded for in appropriate emotions or upsetting others.
To cope the Aspie changes from an open saucepan to a pressure cooker, now the NT can enter the kitchen, and feel relaxed that there is no steam coming of the silent pressure cooker.
I can't talk about your ex, only from my own experience, he may have not be aware of the pressure building up until just before the meltdown sets in. Or he may have a great deal of internal turmoil that he is hiding from you because no NT has ever understood.
Now that it is over, he may be running away from emotions and trying to shut them down, as for him they are far too painful to cope with.
You may find:
Anatomy of a Meltdown informative.
You may also find comments left by other Aspies as to what physical pain they inflict upon themselves to try and block out the intense emotional pain that is an implosion.
If the breakup is a trigger for his meltdowns, he may be avoiding discussing it out of fear of a full blown implosion.