ADVICE PLEASE.!!😩😩

Lissa
So me and my boyfriend lives together... He made me upset because he Waited till when he was about to go out to tell me he was going out then I asked why and he said because it's his friend birthday... He claims he didn't tell me earlier because we were having a serious conversation, which doesn't make since , He didn't even invite me out or anything, Now I'm Just In The House While He's Out getting drunk or something. 
What Should I Say To Him?
 Do I Have A Reason To Be Upset?
ADVICE PLEASE.!!😩😩😩