Are there any girls out there that would be okay with their boyfriend seeing another girl part-time?

I'm 27 and have been dating my girlfriend for almost eight months. We are so completely in love and it is the most special and real relationship I can imagine having. We are both college students at different schools an hour apart. We talk pretty openly about our personal desires, so I've made it clear that like most guys, I am always going to be attracted to other girls no matter how much I love my girlfriend. She's very understanding about that, but she says she isn't attracted to other guys, and I'm pretty sure that's the truth. We only see each other on weekends while in school, which is the only downside to our relationship.

For me, being attracted to a girl is one thing, but developing a real interest in one is pretty rare. I was single for over three years before we started dating because I just couldn't find the right girl. However, two days ago I met another girl in one of my classes that I'm feeling a slight connection with. We were standing in the hall waiting for the teacher to arrive and she kept glancing at me and seemed a little nervous, then she finally turned to me and asked my name. We had a brief conversation and I think we both got some really good vibes. She is cute (definitely my type) and seems very nice and down to earth. But I'm super attracted to my girlfriend in every respect, and she is very nice and down to earth as well. With that said, if I were single, I would fully pursue this new girl further.

I want to be able to hang out with this new girl, but I'm afraid it might lead to something more and there's no way I am comfortable cheating on my girlfriend or taking a risk on losing what we have. It's clear to me that dating two girls openly just doesn't really happen in our culture, but it is also clear that doing so is a natural desire for a lot of guys. I guess I just want some opinions on what my options are. I know that I would feel pretty awful if my girlfriend told me she wanted to date another guy, but I'm not sure how she'd feel about me saying that to her since men and women process a lot of emotions differently and since she seems to understand that men naturally have these piggish urges. There's no question that my girlfriend will always be #1, but it would just be so nice to have some kind of companionship more than one or two days a week.

Yes, I know how ridiculous this is and how upset some people are going to be at me since this is not how the majority of relationships function, but does anyone out there think it's possible to be with two girls at the same time in a non-deceitful way?