I'm interested, what is attractive about being with a girl in general? If I may fall into stereotypes for a moment, one of the common feelings associated with being with a guy is protection or some sense of it (I know that's not all there is to it, but many people would consider it a factor). What is the equivalent for a guy? What makes girls in general attractive?
Sorry if this doesn't make a lot of sense, I'm just interested in trying to understand it.
To answer your question in a suiting stereotype, if girls want the protection, guys want the feeling that they are needed. It boosts their masculinity and their ego.