That's what the relationship becomes between mothers and kids as the kids grow up. Mothers stay crazy about their kids no matter how old or independent those kids get. Kids, on the other hand, outgrow their mothers.
Sometime during adolescence, kids start tossing clues around that maybe spending Saturday afternoon at the mall with Mom isn't on their list of Top Ten Favorites anymore; and that taking a slow trip up the coast with the parents isn't as charming as it used to be; and that, actually, conversing with Mother over a leisurely dinner isn't especially engaging.
It takes a while for mothers to get it, and then it takes a while longer for mothers to accept it. But accept it we must. Because if we aren't raising our kids to be independent and self-sufficient, then what are we raising them for? Mothering them when they were small was important; letting them go when they're grown is equally important. In fact, it's the point.
There comes a time when spending the day shopping or exploring a museum or seeing a movie with you is fun again. They do crave your company sometimes, and not just when they need advice or a babysitter or a place to stay. But once they're grown you aren't the center of their universe anymore, while they stay at the center of yours forever.
And that's just life.