Well for some it's just sex. But you don't really need to have a girlfriend to have a steady flow of it. For me I like to date girls because it's nice having someone that cares about you. And even if it doesn't work out it will help grow as a person. And having a couple long term ones not working out helps you learn what it takes for a relationship to work. So that when you finally are looking someone to settle down with you know what to do.