Given this definition, I can see why you cringe. I think it's typically characteristic of mother to have more concern for others than themselves (children mostly, but their husbands too). However, I feel that this definition is a bit extreme. As a husband, I would never use 'selfless' to complement my wife, if I felt this was the definition. I've always thought it meant very unselfish.

This may be just a matter of degree and your point still stands: we should value our wives and mothers for more than their unselfishness. Otherwise we only encourage them to neglect their own needs. We do not want them to neglect themselves, if we love them. Wives/Mothers need space to experience and enjoy the world around them without always considering the needs of others.