Snowy Owl, my son has aspergers so I see the similarities, but these traits even in aspergers are symptoms. Rigid structure, Obsessive Compulsive behaviours, anxiety and emotional regulation difficulties are all behaviours resulting from a need to control exposure to painful or uncomfortable experiences. I have learned through parenting him and the therapy he has received that all behaviour is just another kind of communication. I don't suggest you try to be a therapist to your H, but understanding his behaviour can make living with it so much easier. For kids with aspergers, the rigid structure all comes down to control. Kids with aspergers have nervous systems that being bombarded constantly so their biological emergency response is constantly in ON position. It is mentally exhausting, so they attempt to control their exposure to "what comes next" in life to make this bearable. I can see a trauma survivor experiencing something similar and, as a result, having similar behaviour. Your husband may have limited his experiences and daily routine in a unconscious attempt to reduce triggers for his csa trauma. This may also make him feel safe from being abused again. In terms of the word "duty", sometimes the language someone uses means something different to us. If he self-limited the spectrum of emotional experiences he could have to cope with his trauma, he may not know the exact word to describe what he feels. Also, "duty" may have been the only thing that kept him living all these years. Maybe a duty to his parents or to god or to you has kept him together and moving forward instead of completely falling apart. I agree with Whome's view of duty versus love too. It is a much safe connection to someone if he was hurt by someone he loved.
I know when I ask my son "why", he acts like I am challenging how he feels to discount it, but when I ask "what" and "how" he feels like I am trying to understand how he experiences life better.
I know there is a world of difference between a child with aspergers and an adult with csa trauma, but if behaviour looks similar, then maybe what it is communicating and attempting to achieve is the same...
I hope this helps.