How can I get my boyfriend to pay more attention to me than he does to his other female friends or friends?

Ok, so my boyfriend always TELLS me that he loves me... and I believe him... It's just kind of hard to be completely sure because it's so easy for him to tell me but he never really shows me except for when we're alone. Lately he's gotten better with the whole PDA thing... but not around his friends really. And then today when we were at lunch one of his girl friends came up to him and tapped him on the shoulder and he smiled up at her and said real cutely "Hey! What are you doing here? I think you're following me." and I guess that just kind of upset me a little.... Any suggestions as to what I can do?