Spoilers ahead! Luke Grimes opens up to ET’s Cassie DiLaura about the creative decision to kill off a major ‘Yellowstone’ character on the new spinoff, ‘Marshals,’ airing Sundays on CBS. Grimes, who reprises the role of Kayce Dutton on the series, reflects on saying goodbye to his on-screen wife, Monica, played by Kelsey Asbille on the Paramount Network hit.
