There are always going to be people in life who are better than you. There are going to be guys who can sing better than I, who can run faster than I can, who can think faster than I can, who are more intelligent, who are more attractive, who are more compassionate- so on and so forth. So it's natural to fear that someone else is going to come along that is better than you are and pose a potential threat to the longevity of your relationship with another person. So maybe, in love, what we really cherish in another person is their flaws- their errors, their mistakes. What they lack is the fire for our heart and its' discourse. Flaws are more personal then the skills of a person- especially when there is always going to be someone who is more skillful.