Should I ask his girlfriend to tag along?

I LOVE this Angel of a Man. I really enjoy hanging out with him and have obviously gotten attached. He has a girlfriend (of course). I haven't met this lucky woman yet, but I'm not sure if I want to. They've been together a few months. I'm afraid that, if she comes and hangs out with "the group", I will not feel special and will end up feeling inadequate because he will be spending time making her comfortable instead of laughing and cracking jokes with me. I know it's selfish, but I don't get the chance to feel special very often. Our group might go to Disneyland in a few weeks, and I'm not sure how to tackle the 'girlfriend' scenario. I know that if I was his girlfriend, I'd want to go and would be offended if I wasn't invited; however, I want him and I to be able to share that kind of experience as us (goofy and nerdy- without censorship due to others being around) Another side of me really wants to meet this lucky girl, but then I might end up feeling left out... what do I do?