I saw a ques on YA today,made me think. I love my wife more than my mum. I cannot live without my wifean my ?

I don't think it is very productive to try to quantify love. I also don't think what you are describing is variance in the amount of love. It is more of a statement of the natural order of things (i.e., your mother is going to die before you, you move out and go on your own...etc). It also has to do with the daily impact on your life as well. That really has nothing to do with love.