The Lagrangian constraint analysis of the selfdual massive spin 2 theory in a 2+1 dimensional flat space-time and its extension to a curved one, are performed. Demanding consistence of degrees of freedom in the model with gravitational interaction, gives rise to physical restrictions on non minimal coupling terms and background. Finally, a constant curvature scenario is explored, showing the existence of forbidden mass values. Causality in these spaces is discussed. Aspects related with the construction of the reduced action and the one-particle exchange amplitude, are noted.Centro de Física Teórica y Computacional, Facultad de Ciencias, Universidad Central de Venezuela, Departamento de Física, Facultad de Ciencias y Tecnología, Universidad de Carabobo.