How many is too much?

Hi peeps, there is a very common question which is often asked when a guy meets a girl and is trying to know her better. What is d question you might ask» 'how many men av u slept  with??'.  I really want to know why guys feel the need  to ask this and how sure are they that they would be  getting the right answer  from the girl in question. hence my question How many is too much???  your  comments are very welcomed