Your not officially dating, so your both able to see other people freely am I correct? If so, bring another date, or just go an enjoy yourself. I think either way because you like this fellow your going to be upset if he brings another girl regardless of whether of not you bring someone else. I assume there's also a good reason why you have this mutual relationship, but aren't a couple. You should also try dating other people, leave yourself open. Worst case scenario, you'll go see him with another girl get upset and make things harder on yourself, or you bring another guy, he doesn't bring a girl, and it gets worse between you to. So your better off thinking of yourself and either calling him and asking him to be your date, or bringing someone you are attracted to or will have a good time with. Like I said, your young enjoy life don't get stuck on one person or one thing too long keep things moving while you can.