Apps are forever tied to the Apple ID that downloaded them originally.
If its asking for your husband's Apple ID, it means it was downloaded with it.
This means your husband was at some point signed in to that iPad with his Apple ID, at least under Settings ➜ Apple ID ➜ Media & Purchases or the iPad was setup using a backup from a device he was signed into. As such any apps that were downloaded to the device the backup used was from would be tied to his Apple ID.
You would need to delete it from your iPad, and download it again with your own Apple ID. This is the only way to stop it from requiring your husband's Apple ID.