Hang on...you don't want to go because you don't like people, but you're son is bad for saying things like, "She didn't want to come, because she doesn't like people"?
If you're going to embrace the life of the solo or you need to, then own it. Don't teach your son that he needs to lie or hide it; to do that very much puts the responsibility for your problems on him as well as your husband.
I'm autistic, and I do recognise all the things you've said here. The one thing that leapt out at me is...the total lack of anything resembling cooperation. What you've described seems more adversarial than anything.
You're married. Why not use that to work on your problems? Without my wife, I would be exactly like you are with anything resembling human contact, and I was. In fact, I was very much like that for the first 10 years of our relationship, until she started to subtly help me with social events. When we discovered about three or four years ago that I'm autistic, we started working way more as a team. She'd cover for me when I needed an exit or a break, she'd steer the conversation away from my oddities, and if I got anxious or started reaching my limit, she'd make herself the centre of attention so I could melt into the background without anybody noticing. That helps me enormously, because it allows me to be as sociable as I can without needing days to recover from it.
Why do I do this, when it's hard work? Because I want her to have a life without having to constantly make excuses for me, and I want to be a part of that life. The marriage isn't all about me, and so I have a responsibility to hold up my end of the bargain both inside and outside the house. Hell, with her as my helper monkey, I can even enjoy social engagements without worrying about an escape plan; that's something I've never been able to say before.
I realise that you're going to read this and think, "Oh, but you don't understand..." and, "Nothing can be done". I do get it. Really, I do. I used to focus entirely on myself and what I was comfortable with too, and it was just ridiculously selfish in the context of a marriage and a family. You're absent from half of their lives. You might be cool with that, and you might be able to rationalise it fairly easily (as you already have done a few times in this thread), but you're not the only one who matters here; think about how they feel about you being missing in action whenever other people are involved.
Start small. It's worth it, and if you choose to...it'll bring you closer together as a family.
But it all starts with an honest, practical conversation without complaints or getting emotional about it.