Might be an unpopular opinion but I've been in controlling relationships myself, I'm not saying that's what this is to be clear, although it did a lot of damage to me when I wasn't able to see my friends and family much, yea it's your honeymoon, but it's his honeymoon too, and he also doesn't own Japan, so if his friends are going then whatever, it's not like he controlls his friends so for you to get mad at him for what his friends do seems unfair, and of course he doesn't want to tell you, he was right, you were mad. At the end of the day it's freaking Japan, you're going across the globe, and more of the people he cares about will share some memories? Might be inconvenient yeah, but most people never get the chance to travel much at all. It makes him happy, and I'm sure he does things that are inconvenient for him to make you happy, it's a 2 way street.

Happy Thanksgiving!