CVS testing of the fetus and DNA testing of the spouse do not really accomplish the same things.

DNA testing of your husband will help you determine if there is the possibility that you may have another child with CAH, so that you can decide ahead of time, if you even want to undergo prenatal treatment. A CVS is usually done after you have ALREADY started prenatal treatment, to determine if you should continue treatment to the end of pregnancy (if you have an affected girl), or if you can stop sooner (if you are carrying a boy or have an unaffected child).

By the time a CVS is performed (~week 9-11), and you get the results back, you would already have passed the window of opportunity when you will get the maximum benefit from the dex. (Doctors usually recommend starting dex ~week 6-9). So, it is really not the right test to use to help you decide if you want to START prenatal treatment.

Therefore, bottom line...yes, it is definitely better to have your husband tested now, in my opinion!