Wanting my wife is a totally physical response to how she looks, behaves, dresses, smells, tempts, excites, talks, ... And, after many years of marriage, she knows how to get my attention.
Needing is, for me, emotional.
Many of us men, unlike many of you ladies, are (sometimes to our detriment) able to put our emotions into a box. We often segregate feelings and then call on them when we want them. It is our way of controlling our world—of protecting ourselves.
There are those days, when I have simply been decimated by the world that I live and work in—when all the defense shields have taken their hits and are weak, when the emotions in the box are seeping through the cracks in the shield and I am losing control. These are the days that I need her—the days that having her close to me, under me, me inside her and she inside me (emotionally, of course—the reverse of the physical act of intercourse).
The wonderful part of it all is that she knows me and is always available to me—waiting to be told that I want her or need her.
You see, I have her very much in hand. And, she has me very much in heart.