<human>: Can you give me the gist of the text in a nutshell?

I've been seeing this guy [23M] for about 5 months now but we aren't exclusive. We've lately fallen into the relationship-y groove but still no title. Tonight I found out he went to dinner with a girl I know he has a history with (they've made out before, he took her to an annual banquet as his date, they went on a hike together, etc). Before this, the last I knew he hung out with her was about 2 months ago. He told me he was too busy to have lunch with me today yet he went to dinner with her.

It really hurt my feelings that he had time to have dinner with her today yet didn't have time to have lunch with me. But I know I have no right to be upset since we aren't exclusive. 

What should I tell him and how do I bring up being exclusive without appearing clingy or over-attached?
<bot>: Upset that the guy I've been seeing went on a date with another girl but we aren't exclusive. How do I bring this and the topic of exclusivity up without appearing clingy?