Now as there are more and more successful women leaders, the message is universal. When your partner is smart and supportive he/she will help you unleash your potential, magnify your strengths, help you with your weakness so you can reach greater heights. In that case, you are lucky and happy. It is tough and lonely to make it without that wonderful support.
PS. There are many version to this joke, mostly about presidents of USA. One is mentioned even in Chicken Soup for the Soul. The version above is the earliest I could find from a 1994 book of quotations.