I assume he’s generally a nice guy or you wouldn’t have married him, but you seem to be blind to the fact he clearly doesn’t want to spend time with your parents and rather than accepting that and finding ways to work around it, you are coming up with ways to get them together.
Could you understand him having anxiety because he finds time with your parents unpleasant? Perhaps they are too gushy or too reserved, too inquisitive, too formal, too laissez faire, too whatever, for him.
If he’s told you the reason he doesn’t want to go was because the idea of travel in general was anxiety inducing, I understand you disbelieving that. I didn’t realise from your first post that that was what he’d said. I thought he’d just said the idea of the holiday gave him anxiety, which isn’t surprising if he doesn’t like spending time with your parents. It seems likely It was a white lie so he doesn’t have to tell you he doesn’t like your parents (or doesn’t like spending time with them).
If you can only have one holiday a year I’m not surprised he’s making up excuses not to go on one with people he doesn’t really want to spend time with. This doesn’t seem so different from him booking a “surprise” trip for you both. And if you can only have one holiday a year, I get why it might be a big deal for him for you to have separate holidays. You might be upset with him if he wanted to spend your one holiday a year with people you don’t like and his solution was to say, well I’ll just go without you, then. That does work for some couples, but for most, giving up your one holiday a year with your spouse to do something without them is not a welcome idea.
His “surprise” holiday is really poor, but it doesn’t seem like you are any more thoughtful of him on the holiday front.
Perhaps it’s time for a more candid conversation about expectations and how you can fit in the things you’d both really like to do. It’s possible that in this regard, you just aren’t very compatible, though.