When should I give up waiting for him to get in touch?

I went on a double blind date last night. The guy is a college football player and he's kinda quiet but really nice and really sexy. Things were going well, the conversation was good, awkward at times but I expected it cuz it was the first time we met. Anyway, he got a phone call during the double-date and was reluctant to answer his phone but he did anyway, and he ended up having to leave to go pick up a girl, like one of his good friends, who was ditched by her bf and friends at a bar with no way of getting home. Before he left, he gave me a big bear hug and said it was nice to meet me.

We didn't exchange numbers or email addresses, but because we met through friends he could easily add me to facebook. When should I give up thinking that he'll probably add me? Or should I add him? Won't that look desperate?