Hi Paul,
Thank you for contacting us. While it's not possible to cover two accounts through the Apple Family Sharing, we do now have a Family Subscription, which provides you with 5 licenses. Is that what you're looking for? You can check out more about all mSecure subscription plans here: msecure.com/plans
You can simply sign in to the same mSecure account on both you and your wife's devices. In this case, you would simply sharing all information you store in the mSecure app. In this case, you'd only be paying for one license.
Does that work for you Paul?
Paul