my bf skipped our plans for his friends

syl
A few days ago, my 3 sisters and I planned a nice Friday date with us and our boyfriends so they can all get to know each other and it was going to be a fun night. we had these plans for almost a week. so after I got off work I reminded him 2 hours before of our plans that were at 7. he didn't text or answer back until 20 minutes before to tell me he told his buddies they'd go out. sooo he ditched our plans and I tried explaining that is was rude but he didn't see it the way I did. I don't want to make him feel bad over it, but I want him to get that I'm pissed and upset about it.....how do I handle this?