Zane told me today about reading an article that explained how "Empty Nest Syndrome" was a myth and that most parents were happier when their kids grew up and left home. While parent's certainly miss their kids, having gone through the stress of the teen years combined with the pride of seeing their children survive on their own generally brings about a positive rather than negative psychological result. I found the following article about it. While it mostly focuses on the woman's perspective, I think the points are pertinent to both parents.
We can certainly attest to the stresses of raising children, especially teenagers since we dove right into the deep end of that one about 6 years ago. I think that the other important point in this article is that you don't stop being a parent just because your children move out. You still care about them, worry about them, have hopes and fears for them and, as we are learning with Jefferson now home from college, they still cause you STRESS! Of course, that is because you still love them and want the best for them and so it is still painful to see them make mistakes, learn hard lessons and be slow to grow in certain ways.
But, most of all, you still love them.