I'm having lunch with my ex..but my boyfriend isn't saying anything..help?

[V3r0_L0v3]

My ex hit me up today on facebook, and he's leaving back for college soon and he wanted to get together and catch up. Me and my ex broke up over two years ago we're just friends. But everytime I mention my ex to my boyfriend I get nervous about his reaction. When I told him we were gonna get lunch, he had just a blank face and I know he doesn't like it but it's just lunch and catch up. Idk I'd feel weird too if it was the other way around but should I just not go to lunch with my ex or should I? I don't want to blow him off but I don't want to upset my boyfriend. Please help