Remember the old Calgon commercials? The mom sitting in the bath tub resting in perfect peace and utter bliss. The kids come screaming at the door and the mom exclaims, "Calgon, take me away!". One great way to minister to your wife is to draw her a warm bath. If she likes bubble baths you can add some bubbles or even her favorite bath salts. Bath and Body Works has an enormous selection of bath products in a multitude of scents that you can get to pull this off.
Make sure to get the bathroom nice and toasty for her before hand. If you want to go all out, light some candles or dim the lights. Once you've got everything prepared, tell her to go enjoy her bath and let her know that you will watch the kids while she has a nice relaxing time to herself.