I will explore two different scenarios to account for the long lifetime of dark matter. In the first one, I will assume that dark matter is stable when coupled to the SM but can proceed through (non-minimal) interactions to gravity. Based on current observations, I will show that even this 'gravitational portal' to dark matter decay is rather constrained. In the second scenario, I will present an extension of the SM where the dark matter candidate can be absolutely stable without the aid of ad hoc additional symmetries.