"Ianthe is not a sanctioned priestess, despite her delusions of grandeur. The wedding ceremony she did is highly illegal, even Tamlin being a High Lord cannot bypass the laws of the Mother and the Cauldron. Rhys saw all when he tore into her mind. Even Tamlin doesn't know she lied to him. It will be quite a shock for him to realize he is not married and thus has no reason to march on us."