How long is too long between contact?

I have a had a few dates with the same guy. Things seem to be going well we have fun together and laugh a lot, but I don't hear from him for sometimes up to two weeks.
I am not disillusioned enough to think that he isn't seeing other people. (I still am), but if he was truly interested wouldn't he call?
We are supposed to be going out this weekend. He was cooking dinner and then we were going to a show. It's two days before the date and I haven't heard from him in 10 days. There has been no time set to meet and he knows I have the tickets. When do I offer the tickets to someone else and just write it off as a growth opportunity?