Oh, don't worry, most kids will be in and out for years.

Thats the worst part. First you adjust to them being gone and then you have to adjust to them being back home again.

Eventually the tide turns and you find yourself wanting to live closer to them - not next door but at least in the same town. You might even be lucky enough to move into their in-law suite when the baby is born.

In the meantime, get to know them as adults and pat yourself on the back for raising independent kids even when you realize that you are dependent on them for a great deal of your happiness.