Yes… it’s part of the disorder. And, there are several important reasons why people with Asperger’s and High-Functioning Autism are “inflexible” (to use your term). We call this “cognitive rigidity”:
The brains of people on the spectrum are structurally normal, but “dysregulated” (i.e., there is an impaired regulation of a bundle of neurons in the brain stem that processes sensory signals from various areas of the body).
Cortisol is a key factor in understanding Asperger’s (ASD level 1). It is one of several stress hormones that acts similar to a red alert that is triggered by stressful circumstances, which helps the person to react quickly to changes. In neurotypical (non-Asperger's) people, there is a two-fold increase in levels of cortisol within 30 minutes of waking up – and levels gradually declining during the day as part of the internal body clock.
They don’t adjust normally to the challenge of a new environment on waking, which may affect the way they subsequently engage with the world around them. By viewing your husband’s symptoms as a “stress response” rather than stubbornness may help you develop a few techniques for avoiding circumstances contribute to his anxiety.
Executive Dysfunction (more information here)—
This deals with impulse control, inhibition, mental flexibility, planning, the initiation/monitoring of action, and working memory. This explains some of the symptoms of Asperger’s (e.g., poor social interaction due to a defect in cognitive shifting, repetitive and restricted behavior).
Theory of Mind Deficit (more information here)—
Theory of mind is the intuitive understanding of one’s mental state -- and the mental state of others (i.e., emotions, thoughts, beliefs, perceptions, knowledge, intentions and desires – and of how those mental states influence behavior). Your husband most likely has great difficulty understanding others thoughts, feelings, and motivations, which is the core cognitive deficit.
Weak Central Coherence—
This is the inability to understand the context of a situation or to see the big picture. This explains common behaviors found Asperger’s (e.g., repetitiveness, focusing on parts of objects, persistence in behaviors related to details, etc.).
I hope that makes sense. Thanks for the question.
Resources for Neurodiverse Couples:==> Online Group Therapy for Men with ASD