I’m sorry you had such a negative reaction; remember that says so much more about them than it does about you!
I was diagnosed at 24 with ASD and my family don’t get it either! I also found that when I was newly diagnosed that I was suddenly acutely aware of my ASD traits and that really knocked my confidence about what I could and couldn’t do due to my ASD. I slowly came to realise that I was the same person as I was pre-diagnosis, I was just now hyper aware of my so called faults and that was making me really unconfident.
I changed my focus to looking at what support the diagnosis would give me rather than what traits it highlighted. So instead of looking at my social shortcomings, I used it to start learning what social scenarios I did best in and which were more challenging. Then I started avoiding some of the more challenging ones that didn’t benefit me or weren’t essential, leaving me more energy for ones which I couldn’t avoid- I then had more headspace to come up with strategies to cope with them.
So rather than withdrawing from everything challenging when you have ASD I basically became selective and started to identify what resources I had/what were my limits and use that as wisely as I can. I still don’t get it 100% right but I try my best and I can accept getting it wrong some of the time, if I know I am trying!
An example would be that I often let my husband visit the in laws alone, however I will make the effort for birthdays/Xmas etc. My husband stays out late when he goes alone, but when we go together he comes home earlier with me- this works for both of us.
You should work with your husband so that he supports you in the most useful way to you, but not 24/7 so that he still has downtime and his own life- your idea of him going alone and coming back for bedtime sounds good, or could he stay home earlier, get the kids to bed and then go out for the late part?
come over to the Neurodiverse board and meet more of us- there are lots of people at different stages of the process and you may feel better to know you are not alone!
to reiterate- your in laws sound like arses!