I am assuming you are signing into the NowTV App on the Apple TV box using your account details and not your husbands Apple ID details and you have bought a NowTV Pass via the NowTV website under the My Account > Passes & Vouchers section ?
Maybe see if anything in this help article points you in the right direction.
Should have said that you don't need to buy another pass if you have already an active pass on your NowTV account, under the My Account > Passes & Vouchers section.
If you are signing into the NowTV App with your correct NowTV account details and it won't play your passes, then maybe try signing out of the box, delete the App, then re install the App, then once the App is installed, power down the Apple TV and switch it off at the mains for a minute.
Then re start the ATV box and sign back into the App with your NowTV account email address or alternatively with your nowtv username (not forum name).
Otherwise see if NowTV live chat can help you out.