How to get a guy to ask you to be his girlfriend?

I live a lifestyle where I like to go out and have a good time and party on occasion. I enjoy traveling, but I am also very well rounded and have a great career. I am told atleast once a day that I am attractive by different guys. Guys always ask for my number, but I always somehow get put into the "fun, not girlfriend material" category..wth? I'm not pushing or anxious to have a boyfriend but don't understand why this happens everytime..what makes guys automatically put girls into this category?