I'm upset that my boyfriend chose to out this evening
Why are you upset about him going out?
He should be doing other things
Its not realistic to think your boyfriend will always be able to cater to what you want. If you see a pattern in him doing this then there could be an issue, if this is just a one time thing then you should be easy on him.
I think he'll always want to be with me and I'll always get what I want.
A relationship is a two way street. You need to think about what he needs and wants too instead of expecting him to do what you want him to all the time.