My boyfriend doesn't want me talking to my co-worker?

I started working at a grocery store in June, right after I graduated highschool. I met this guy at my work, who I kind of was attracted to. It was an attraction, but I didn't want to date him or anything. Afterall, I already had a boyfriend. I ended up telling both my boyfriend and the guy (which was probably stupid) and after awhile the attraction went away. I love my boyfriend, we've been together for almost two years. I work with that one guy still and we joke around and stuff. His car is designed to look like the slugbug Herbie. He is currently working on Herbie because it broke down. He told me that when it is fixed that I can ride in it if I want (this guy is 23 and he isn't really all that interested in hanging out with me, he was just being nice. I think he only sees me as a work friend)... however my boyfriend says he doesn't really want me hanging out with him outside of work because of the attraction. I'm not attracted to this guy anymore, like we barely even talk. Do you think that this is ridiculous? I only want to ride in his car, because it's kind of like something cool and exciting in our small town... I dont know if he's over reacting. HE doesn't even know my co-worker, and yet he says he jsut doesn't like him and gets a bad vibe from him.