If you sign up for part A you are on the right track. You won't need a secondary for the other 20 percent because you DH' insurance will act as that. i would call your husband's company and they will tell you for sure. Medicare approves a certain amount of the bill and then medicare pays 80 percent of the approved amount and the other 20 is picked up by the secondary. And always ask your doctors is they accept what medicare approves. If they do then is there is anything over and above that the doctor's office writes that off. Hope this helps understand this mess. suzanne