Is there anywhere people have found that is good for explaining what this is, while coming from an adult's perspective?

I am also looking to see if there are any resources on caretaker fatigue, especially with "invisible illnesses" or constant issues like SPD.

My partner has grown to accept it as a thing that happens, and is trying to be super helpful, they understand the things I have trouble with and help me avoid those, but I still hear the occasional incredulous "you have a problem with x?" or "it's your body, everybody else has one too, just get used to it" They understand people being introverts and not liking to be touched, but it seems to be more of the "they just don't like to be touched" not "you touch too lightly and their skin crawls for a few minutes after". They understand misophonia and chewing being initially rage-inducingly annoying, but they say they could just ignore it if it were a constant. I can't quite bridge the gap between that initial sensory overload and complete understanding of how any of the other senses could be that level of problematic.

Tell them that your senses are a bit of mess and the volume is up too loud, be honest with them about the things that are bugging you, however, also work with them to make those things less of an issue for you. Like if you need to wear earplugs during eating to help, or listen to music. Just say I need a warning so I can deal properly. Sometimes though you need to know when to walk away before things get too much. Just tell them that when you leave you just need your alone time. If they really do love you they will respect and try their best to work with you.