A magnetic seal assembly comprises a metallic annular wear seal. A magnetic seal has a magnetic annular body adjacent to and attracting the wear seal into contact against a contact face thereof. A retainer ring is connected to a surface to the magnetic seal, the retainer ring having a coefficient of thermal expansion different than a coefficient of thermal expansion of the annular body, the coefficient of thermal expansion of the retainer ring selected to constrain a thermal expansion of the annular body. A method for controlling a thermal expansion of a magnetic seal assembly is also provided.