I want to talk about this.
We've had a few people who truly thought this was correct, and wrote books, blogs and other material on the subject. Some called it 'Cassandra Syndrome', and then changed that name to 'Affective Deprivation Disorder', (AfDD). both entirely made-up things.
http://www.maxineaston.co.uk/cassandra/ needs a content-warning. In this, various pieces of out of date and incorrect information combine. Here is an extract.
"AfDD is about emotional deprivation caused by living in an intimate relationship where the one partner is affected by a low emotional intelligence or Alexithymia.
My research strongly indicates that AfDD can develop as a consequence of being in an intimate relationship with an adult with a disorder that produces a low emotional/empathic quotient or Alexithymia, a Greek term meaning literally without words for feelings (Parker, Taylor and Bagby 2001).
Alexithymia levels found in Autistic Spectrum Disorders are [85%] (Hill, Bethoz and Frith 2004), Anorexia Nervosa [63%] and Bulimia [56%] (Cochrane, Brewerton, Wilson and Hodges 1993), Major Depressive Disorder [45%] (Honkalampi et al. 2001), Posttraumatic Stress Disorder [40%] (Shipko, Alvarez and Noviello 1983), Panic Disorder [34%] (Cox, Swinson, Shulman and Bourdeau 1995).
The prevalence of Alexithymia is highest in people with an Autistic Spectrum disorder (85%) which is further hindered by a lack of theory of mind (Beaumont and Newcombe 2006)."
Let's have a look at this invented 'disorder'.
Firstly, autism itself is not a disorder. It is a neurodivergence. We are autistic for life, from birth, and it is a genuinely different way of communicating. See https://annsautism.blogspot.com/2019/01/autism-some-vital-research-links.html for a huge amount of info on the positives and differences, from actual modern research.
Second, autistic people may need time to process emotions and to be able to describe those in words. This is not the same as having no emotions, or not caring, or having 'low empathy'. Emotional responses may be shown through autistic communication, not through language.
Both parties - autistic and non-autistic, have a different way of expressing emotion, and a different set of basic relationship needs. Both have different ways of using eye contact, face expression, body language, body positioning, use of touch, voice tone and language. To work a good relationship with one another, both parties need to realise that the other is different, and both parties need to find ways for the other person to thrive. Therefore both parties are potentially 'low' in empathy for the other party, not just the autistic person. I would strongly advise searching online for the Double Empathy work by Damian Milton. http://www.thinkingautismguide.com/2019/05/the-problem-with-autistic-communication.html is also helpful.
Yet, if you follow those research links in my other blog, it's clear that most autistic people do not in fact lack empathy at all. (Using the word 'empathy' to mean caring about what happens to other people, rather than technical versions of the word). Most are deeply caring about others, and deeply helpful. Most give generously to charity, most are very fair, most are very honest and keen to see social justice. But...they may not be able to 'perform empathy', in the expected ways. And there will be a cultural expectation from the autistic person that their partner will state their needs. This is actually really simple. "I need a hug now". "It is our anniversary soon and I would like...". These are not world-ending things to attempt. In both-autistic relationships, frequently there's great success, because both generally can learn quite fast how the other communicates.
There is also a 'before' to this. Whilst some claim that they had no idea whatsoever that the autistic person was autistic before (e.g.) marrying them, I would suggest that knowing almost nothing about your partner before marrying them is not something to blame entirely on their partner. A number of autistic people certainly can 'mask', out of terrifying fear from a lifetime of violence, assault, bullying and exclusion, defrauding, ostracism and worse from some non-autistic people. But those are almost impossible to keep up for long without absolute exhaustion, shutdown or meltdown. Certainly some autistic adults don't know they are autistic, and some end up with other diagnoses because diagnostic teams haven't been good at spotting (e.g.) females, extraverts, People of Colour, etc who are autistic. But if you are utterly incompatible, emotionally, the time to say this is a bad relationship is probably before you move in together.
I see some who claim that their partner is autistic because they are deliberately nasty and abusive, violent or otherwise. When quizzed on this, generally they reveal that actually their partner has no diagnosis, and this is just what they've been told by someone who believes in Cassandra Syndrome. Shocking stuff, actually. There is no link to greater deliberate violence because of autism, in any research at all. If an autistic person enters a brain event called a meltdown, it's linked to spikes in brain electricity, on the latest research. In other words, it's similar to a form of epilepsy, not a choice. Not that many autistic people have such meltdowns. In surveys, some 7 out of 10 report they have shutdowns, where they cannot talk or move much, as part of this. Not exactly dangerous....
In the same way, a friend who is diabetic may enter a seemingly angry state when their blood sugar level is wrong. That's not them being deliberately horrible to control you.
Could, in theory, an autistic person also be a nasty person? Yes, but no more likely than anyone else being a nasty person. Being autistic is not the cause of nastiness.
As for a lack of theory of mind, no. Research shows clearly that by adult years, autistic people are fine with understanding that others have different needs and beliefs. It is a difference in how our responses look, and what we can manage in different environments - not a cluelessness.
So, Cassandra Theory is a mess. Autistic people generally have terrible outcomes in life. Average age of death believed to be around the mid-50s, because the stress, strain and suicidality that results. That's not evil on our part, nor is it a lack of caring or a lack of effort.
Let's look at something helpful instead.
If you find that you are not understanding your partner, and it's distressing, you can seek good help and support from an autism-trained, gentle, affirming relationship counsellor. There are some out there.
You can read materials written by autistic people around relationships.
You can work on communication together.
You can learn to ask good questions of one another, using whatever works (which might be by text or email rather than spoken language, as autistic people may genuinely not be able to use spoken language when exhausted or in sensory/social overload.)
You can learn that an autistic person fleeing from a party or other social gathering is not a sign of lack-of-effort or lack-of-caring, by watching this https://vimeo.com/52193530 with the sound turned up as loud as you can handle without running out of the room yourself.
Two minutes of the most powerful animation I know, explaining how the world is for an autistic young person. They're not 'failing to care', they in absolute nightmare amounts of pain and distress. The 'failing to care' isn't happening from either party here; after all, the non-autistic person did not know that their partner was in that much pain and distress.
You can learn that an autistic person failing to put the bins out is not a sign that they wish to dump all the tasks on you, but may be a function of being overloaded with sensory/social input, crashing their brain's task-doing centre. There's ways to work with people to get the right balance. Or to agree to get in some outside support, where available.
If you decide you cannot continue in a relationship, fair enough. A number of relationships do fail, whether autistic or not. But blaming 'autism' isn't OK. Research has moved way, way beyond those old myths of the uncaring partner. Autism was never that.
Thank you for reading.