I dread my boyfriend going to a rave party.
Did something happen to make you dislike raves?
I had some bad experiences in the past at raves.
You don't have to go to a party you don't want to, but you should talk about the bad things if they're still bothering you and not try to prevent him from going to soothe your emotions.
I am trying to treat it like normal this time, but I am having a hard time not being scared for him.
I understand that you are scared of raves based on your past experiences, but you are interfering with your bf when you don't want him to go to one. Deal with your own issues internally rather than trying to control others around you externally.